Assignment of proxies for virtual-machine secondary copy operations including streaming backup job

ABSTRACT

A comprehensive approach to streaming backups for virtual machines (“VMs”) in a storage management system comprises improvements to the assignment of data agent proxies for VM secondary copy operations. New considerations in performing a VM streaming backup job include without limitation: determining and enforcing a system-wide per-proxy limit of concurrent data streams; generating an ordered priority list of the VMs to be backed up as a basis for choosing which proxies will back up the respective VM, though the illustrative system may not strictly adhere to the priority list based on further considerations; identifying a next available proxy based on data stream utilization at the proxy; and dynamically re-generating the priority list and re-evaluating considerations if some VMs become “stranded” due to a failure to be backed up. Secondary copy operations are distributed to proxies in ways that improve the chances of successfully completing VM streaming backups.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.14/745,130 filed on Jun. 19, 2015 and entitled “Assignment of Proxiesfor Virtual-Machine Secondary Copy Operations Including Streaming BackupJobs.” Any and all applications for which a foreign or domestic priorityclaim is identified in the Application Data Sheet of the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentand/or the patent disclosure as it appears in the United States Patentand Trademark Office patent file and/or records, but otherwise reservesall copyrights whatsoever.

BACKGROUND

Businesses worldwide recognize the commercial value of their data andseek reliable cost-effective ways to protect the information stored ontheir computer networks. A company might back up critical computingsystems such as databases, file servers, web servers, and so on as partof a daily, weekly, or monthly maintenance schedule. The company maysimilarly protect virtual machine resources, which are becomingincreasingly popular platforms for a variety of business uses. One ofthe perennial challenges is to protect the company's data in a way thatmakes efficient use of resources, while reducing the impact onproductivity and network resources.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram illustrating an exemplary informationmanagement system.

FIG. 1B is a detailed view of a primary storage device, a secondarystorage device, and some examples of primary data and secondary copydata.

FIG. 1C is a block diagram of an exemplary information management systemincluding a storage manager, one or more data agents, and one or moremedia agents.

FIG. 1D is a block diagram illustrating a scalable informationmanagement system.

FIG. 1E illustrates certain secondary copy operations according to anexemplary storage policy.

FIGS. 1F-1H are block diagrams illustrating suitable data structuresthat may be employed by the information management system.

FIG. 2A is a block diagram illustrating some salient portions of asystem 200 for improving the assignment of data agent proxies invirtual-machine secondary copy operations including streaming backupjobs according to an illustrative embodiment of the present invention.

FIG. 2B is a block diagram illustrating some salient details of system200, including a virtual machine cluster 202 and its constituentcomponents.

FIG. 2C is a block diagram illustrating some salient details of system200, including virtual-server data agent proxies 1-3, a coordinator dataagent 242-1, and controller data agents 242-2 and 242-3.

FIG. 3 depicts some salient operations of a method 300 according to anillustrative embodiment of the present invention.

FIG. 4 depicts some salient sub-operations of block 304 of method 300.

FIG. 5 depicts some salient sub-operations of block 306 of method 300.

FIG. 6 depicts some salient sub-operations of block 504 in block 306 ofmethod 300.

FIG. 7 depicts some salient sub-operations of block 308 of method 300.

FIG. 8 depicts some salient sub-operations of block 704 in block 308 ofmethod 300.

DETAILED DESCRIPTION

With the popularity of virtual machines (“VMs”) progressivelyincreasing, data that is generated and/or used by virtual machines maybecome correspondingly more valuable. Thus, backing up virtual machinedata stores takes on added importance, especially with a view to betterutilization of resources such as data agents for virtual machines andnetwork resources in which these virtual machines operate. Althoughprior attempts were made to load balance amongst data agents for virtualmachines (or “virtual server data agents” or “virtual server agents”),the embodiments according to the present invention take a more nuancedmulti-dimensional approach that considers several dynamic factors in thecourse of planning and executing virtual machine secondary copyoperations, including streaming backup jobs. Some prior art approachesare described in U.S. Patent Application Publications 2014/0196038 A1and 2014/0196056 A1, which were both filed on Jan. 6, 2014 with thetitle “Virtual Server Agent Load Balancing,” and which are bothincorporated by reference in their entirety herein.

Traditional load balancing techniques used for assigning resources tosecondary copy operations such as streaming backup jobs may be deficientin the way in which the backup resources are actually utilized in astorage management system. For example, data agent proxies may becomeover-utilized or under-utilized when viewed at the system-wide levelacross several concurrent backup jobs. In some cases, virtual machines(“VMs”) that are targeted for a particular backup job are not backed upin a timely manner or at all, because of over-extended or failedproxies. In some cases, a backup job may take a toll on the performanceof primary storage devices that store virtual machine data due to backupattempts that over-tax the primary storage devices. The need thereforeexists for improved performance, timeliness, scalability, and faulttolerance when backing up virtual machines.

The present inventor devised a more comprehensive approach to streamingbackups for virtual machines in a storage management system. Thecomprehensive approach comprises improvements to the assignment of dataagent proxies for conducting VM secondary copy operations. Theimprovements include a number of new considerations that are introducedin the course of performing a VM streaming backup job, including withoutlimitation:

-   -   Determining and enforcing a per-proxy maximum limit of        concurrent data streams that may be allowed for backup        operations at any given time, regardless of how many backup jobs        may be supported by the proxy;    -   Generating an ordered priority list of the virtual machines to        be backed up in the backup job, such that the priority list        provides a basis for choosing which proxies will perform the        backup of the respective virtual machine—although, notably, the        illustrative system may depart from strict adherence to the        priority list based on further considerations;    -   The ordering of the virtual machine priority list involves        identifying proxies that are eligible to back up each virtual        machine based on tiered modes of access to the respective        virtual machine's data store; e.g., direct and local access to        data stores is generally favored over networked access, in order        to allow for faster data movement using fewer resources;    -   The ordering of the virtual machine priority list is based on        assigning higher priority to virtual machines having fewer        eligible proxies in favor of virtual machines that have more        choices of eligible proxies, so that more limited virtual        machines may be backed up sooner to avoid becoming stranded;    -   The ordering of the virtual machine priority list is also based        on assigning higher priority to virtual machines having        relatively more total storage (i.e., bigger data stores) in        favor of virtual machines that have less total storage for their        data store, because smaller virtual machines may be less likely        to become stranded as the backup job progresses;    -   Identifying a next available proxy for a backup operation based        on data stream utilization at the proxy, such that currently        idle or lightly loaded proxies are favored over busier proxies        in order to better balance backup processes across proxies;    -   Identifying a virtual machine for the next backup operation is        based not only on its position in the ordered priority list, but        is further based on whether the proxy identified as next        available is eligible to back up the virtual machine, which may        favor a lower-priority virtual machine rather than strict        adherence to the ordering of the priority list;    -   Identifying a virtual machine for the next backup operation is        further based on whether the virtual machine's data store has a        relatively low level of backup access thereto, which may favor a        lower-priority virtual machine rather than strict adherence to        the ordering of the priority list;    -   Re-evaluating the choice of next available proxy throughout the        course of the backup job, such as after a virtual machine has        been backed up, and after a virtual machine backup operation has        started at a proxy;    -   Dynamically re-generating the priority list and re-evaluating        the above-mentioned considerations if some virtual machines        become “stranded” due to a failure to be backed up in a first        traversal of the priority list, such that the backup job        restarts with respect to only the stranded virtual machines and        the proxy access-mode tier limitations are relaxed in order to        broaden the field of eligible proxies and enhance fault        tolerance.

Applying one or more of these considerations, in any combination, willtend to improve performance and fault tolerance in VM streaming backups,by taking a more dynamic approach that is responsive to currentconditions in the storage management system (e.g., busy proxies, busydata stores, network bottlenecks, out-of-service components, etc.). Theillustrative approach distributes secondary copy operations to proxiesin ways that improve the chances of successfully completing VM streamingbackups. Moreover, the illustrative approach is tolerant of proxies thatare out of service or have otherwise failed to perform a backup withoutnecessarily needing to restart the backup job. These and otheradvantages are described in more detail below.

The passages above serve to summarize some of the considerationsdisclosed in the present patent document in order to ease the reader'sunderstanding. Detailed descriptions and examples of systems and methodsaccording to the present invention may be found in the section entitledIMPROVING THE ASSIGNMENT OF DATA AGENT PROXIES FOR EXECUTINGVIRTUAL-MACHINE SECONDARY COPY OPERATIONS INCLUDING STREAMING BACKUPJOBS, as well as in the section entitled Example Embodiments, and alsoin FIGS. 2A-8 herein. Furthermore, components and functionality forimproving the assignment of data agent proxies for executingvirtual-machine secondary copy operations may be configured and/orincorporated into information management systems such as those describedherein in FIGS. 1A-1H.

Information Management System Overview

With the increasing importance of protecting and leveraging data,organizations simply cannot afford to take the risk of losing criticaldata. Moreover, runaway data growth and other modern realities makeprotecting and managing data an increasingly difficult task. There istherefore a need for efficient, powerful, and user-friendly solutionsfor protecting and managing data.

Depending on the size of the organization, there are typically many dataproduction sources which are under the purview of tens, hundreds, oreven thousands of employees or other individuals. In the past,individual employees were sometimes responsible for managing andprotecting their data. A patchwork of hardware and software pointsolutions has been applied in other cases. These solutions were oftenprovided by different vendors and had limited or no interoperability.

Certain embodiments described herein provide systems and methods capableof addressing these and other shortcomings of prior approaches byimplementing unified, organization-wide information management. FIG. 1Ashows one such information management system 100, which generallyincludes combinations of hardware and software configured to protect andmanage data and metadata, which is generated and used by the variouscomputing devices in information management system 100. The organizationthat employs the information management system 100 may be a corporationor other business entity, non-profit organization, educationalinstitution, household, governmental agency, or the like.

Generally, the systems and associated components described herein may becompatible with and/or provide some or all of the functionality of thesystems and corresponding components described in one or more of thefollowing U.S. patents and patent application publications assigned toCommvault Systems, Inc., each of which is hereby incorporated in itsentirety by reference herein:

-   -   U.S. Pat. No. 7,035,880, entitled “Modular Backup and Retrieval        System Used in Conjunction With a Storage Area Network”;    -   U.S. Pat. No. 7,107,298, entitled “System And Method For        Archiving Objects In An Information Store”;    -   U.S. Pat. No. 7,246,207, entitled “System and Method for        Dynamically Performing Storage Operations in a Computer        Network”;    -   U.S. Pat. No. 7,315,923, entitled “System And Method For        Combining Data Streams In Pipelined Storage Operations In A        Storage Network”;    -   U.S. Pat. No. 7,343,453, entitled “Hierarchical Systems and        Methods for Providing a Unified View of Storage Information”;    -   U.S. Pat. No. 7,395,282, entitled “Hierarchical Backup and        Retrieval System”;    -   U.S. Pat. No. 7,529,782, entitled “System and Methods for        Performing a Snapshot and for Restoring Data”;    -   U.S. Pat. No. 7,617,262, entitled “System and Methods for        Monitoring Application Data in a Data Replication System”;    -   U.S. Pat. No. 7,747,579, entitled “Metabase for Facilitating        Data Classification”;    -   U.S. Pat. No. 8,156,086, entitled “Systems And Methods For        Stored Data Verification”;    -   U.S. Pat. No. 8,170,995, entitled “Method and System for Offline        Indexing of Content and Classifying Stored Data”;    -   U.S. Pat. No. 8,229,954, entitled “Managing Copies Of Data”;    -   U.S. Pat. No. 8,230,195, entitled “System And Method For        Performing Auxiliary Storage Operations”;    -   U.S. Pat. No. 8,285,681, entitled “Data Object Store and Server        for a Cloud Storage Environment, Including Data Deduplication        and Data Management Across Multiple Cloud Storage Sites”;    -   U.S. Pat. No. 8,307,177, entitled “Systems And Methods For        Management Of Virtualization Data”;    -   U.S. Pat. No. 8,364,652, entitled “Content-Aligned, Block-Based        Deduplication”;    -   U.S. Pat. No. 8,578,120, entitled “Block-Level Single        Instancing”;    -   U.S. Pat. Pub. No. 2006/0224846, entitled “System and Method to        Support Single Instance Storage Operations”;    -   U.S. Pat. Pub. No. 2009/0319534, entitled “Application-Aware and        Remote Single Instance Data Management”;    -   U.S. Pat. Pub. No. 2012/0150818, entitled “Client-Side        Repository in a Networked Deduplicated Storage System”;    -   U.S. Pat. Pub. No. 2012/0150826, entitled “Distributed        Deduplicated Storage System”;    -   U.S. Pat. Pub. 2014/0196038 A1, entitled “Virtual Server Agent        Load Balancing”; and    -   U.S. Pat. Pub. 2014/0196056 A1, entitled “Virtual Server Agent        Load Balancing”.

The information management system 100 can include a variety of differentcomputing devices. For instance, as will be described in greater detailherein, the information management system 100 can include one or moreclient computing devices 102 and secondary storage computing devices106.

Computing devices can include, without limitation, one or more:workstations, personal computers, desktop computers, or other types ofgenerally fixed computing systems such as mainframe computers andminicomputers. Other computing devices can include mobile or portablecomputing devices, such as one or more laptops, tablet computers,personal data assistants, mobile phones (such as smartphones), and othermobile or portable computing devices such as embedded computers, set topboxes, vehicle-mounted devices, wearable computers, etc. Computingdevices can include servers, such as mail servers, file servers,database servers, and web servers.

In some cases, a computing device includes virtualized and/or cloudcomputing resources. For instance, one or more virtual machines may beprovided to the organization by a third-party cloud service vendor. Or,in some embodiments, computing devices can include one or more virtualmachine(s) running on a physical host computing device (or “hostmachine”) operated by the organization. As one example, the organizationmay use one virtual machine as a database server and another virtualmachine as a mail server, both virtual machines operating on the samehost machine.

A virtual machine includes an operating system and associated virtualresources, and is hosted simultaneously with another operating system ona physical host computer (or host machine). A hypervisor (typicallysoftware, and also known in the art as a virtual machine monitor or avirtual machine manager or “VMM”) sits between the virtual machine andthe hardware of the physical host machine. One example of hypervisor asvirtualization software is ESX Server, by VMware, Inc. of Palo Alto,Calif., USA; other examples include Microsoft Virtual Server andMicrosoft Windows Server Hyper-V, both by Microsoft Corporation ofRedmond, Wash., USA, and Sun xVM by Oracle America Inc. of Santa Clara,Calif., USA. In some embodiments, the hypervisor may be firmware orhardware or a combination of software and/or firmware and/or hardware.

The hypervisor provides to each virtual operating system virtualresources, such as a virtual processor, virtual memory, a virtualnetwork device, and a virtual disk. Each virtual machine has one or morevirtual disks. The hypervisor typically stores the data of virtual disksin files on the file system of the physical host machine, called virtualmachine disk files (in the case of VMware virtual servers) or virtualhard disk image files (in the case of Microsoft virtual servers). Forexample, VMware's ESX Server provides the Virtual Machine File System(VMFS) for the storage of virtual machine disk files. A virtual machinereads data from and writes data to its virtual disk much the same waythat an actual physical machine reads data from and writes data to anactual disk.

Examples of techniques for implementing information managementtechniques in a cloud computing environment are described in U.S. Pat.No. 8,285,681, which is incorporated by reference herein. Examples oftechniques for implementing information management techniques in avirtualized computing environment are described in U.S. Pat. No.8,307,177, also incorporated by reference herein.

The information management system 100 can also include a variety ofstorage devices, including primary storage devices 104 and secondarystorage devices 108, for example. Storage devices can generally be ofany suitable type including, without limitation, disk drives, hard-diskarrays, semiconductor memory (e.g., solid state storage devices),network attached storage (NAS) devices, tape libraries or othermagnetic, non-tape storage devices, optical media storage devices,DNA/RNA-based memory technology, combinations of the same, and the like.In some embodiments, storage devices can form part of a distributed filesystem. In some cases, storage devices are provided in a cloud (e.g., aprivate cloud or one operated by a third-party vendor). A storage devicein some cases comprises a disk array or portion thereof.

The illustrated information management system 100 includes one or moreclient computing device 102 having at least one application 110executing thereon, and one or more primary storage devices 104 storingprimary data 112. The client computing device(s) 102 and the primarystorage devices 104 may generally be referred to in some cases as aprimary storage subsystem 117. A computing device in an informationmanagement system 100 that has a data agent 142 installed and operatingon it is generally referred to as a client computing device 102 (or, inthe context of a component of the information management system 100simply as a “client”).

Depending on the context, the term “information management system” canrefer to generally all of the illustrated hardware and softwarecomponents. Or, in other instances, the term may refer to only a subsetof the illustrated components.

For instance, in some cases, the information management system 100generally refers to a combination of specialized components used toprotect, move, manage, manipulate, analyze, and/or process data andmetadata generated by the client computing devices 102. However, theinformation management system 100 in some cases does not include theunderlying components that generate and/or store the primary data 112,such as the client computing devices 102 themselves, the applications110 and operating system operating on the client computing devices 102,and the primary storage devices 104. As an example, “informationmanagement system” may sometimes refer to one or more of the followingcomponents and corresponding data structures: storage managers, dataagents, and media agents. These components will be described in furtherdetail below.

Client Computing Devices

There are typically a variety of sources in an organization that producedata to be protected and managed. As just one illustrative example, in acorporate environment such data sources can be employee workstations andcompany servers such as a mail server, a web server, a database server,a transaction server, or the like. In the information management system100, the data generation sources include the one or more clientcomputing devices 102.

The client computing devices 102 may include any of the types ofcomputing devices described above, without limitation, and in some casesthe client computing devices 102 are associated with one or more usersand/or corresponding user accounts, of employees or other individuals.

The information management system 100 generally addresses and handlesthe data management and protection needs for the data generated by theclient computing devices 102. However, the use of this term does notimply that the client computing devices 102 cannot be “servers” in otherrespects. For instance, a particular client computing device 102 may actas a server with respect to other devices, such as other clientcomputing devices 102. As just a few examples, the client computingdevices 102 can include mail servers, file servers, database servers,and web servers.

Each client computing device 102 may have one or more applications 110(e.g., software applications) executing thereon which generate andmanipulate the data that is to be protected from loss and managed. Theapplications 110 generally facilitate the operations of an organization(or multiple affiliated organizations), and can include, withoutlimitation, mail server applications (e.g., Microsoft Exchange Server),file server applications, mail client applications (e.g., MicrosoftExchange Client), database applications (e.g., SQL, Oracle, SAP, LotusNotes Database), word processing applications (e.g., Microsoft Word),spreadsheet applications, financial applications, presentationapplications, graphics and/or video applications, browser applications,mobile applications, entertainment applications, and so on.

The client computing devices 102 can have at least one operating system(e.g., Microsoft Windows, Mac OS X, iOS, IBM z/OS, Linux, otherUnix-based operating systems, etc.) installed thereon, which may supportor host one or more file systems and other applications 110.

The client computing devices 102 and other components in informationmanagement system 100 can be connected to one another via one or morecommunication pathways 114. For example, a first communication pathway114 may connect (or communicatively couple) client computing device 102and secondary storage computing device 106; a second communicationpathway 114 may connect storage manager 140 and client computing device102; and a third communication pathway 114 may connect storage manager140 and secondary storage computing device 106, etc. (see, e.g., FIG. 1Aand FIG. 1C). The communication pathways 114 can include one or morenetworks or other connection types including one or more of thefollowing, without limitation: the Internet, a wide area network (WAN),a local area network (LAN), a Storage Area Network (SAN), a FibreChannel connection, a Small Computer System Interface (SCSI) connection,a virtual private network (VPN), a token ring or TCP/IP based network,an intranet network, a point-to-point link, a cellular network, awireless data transmission system, a two-way cable system, aninteractive kiosk network, a satellite network, a broadband network, abaseband network, a neural network, a mesh network, an ad hoc network,other appropriate wired, wireless, or partially wired/wireless computeror telecommunications networks, combinations of the same or the like.The communication pathways 114 in some cases may also includeapplication programming interfaces (APIs) including, e.g., cloud serviceprovider APIs, virtual machine management APIs, and hosted serviceprovider APIs. The underlying infrastructure of communication paths 114may be wired and/or wireless, analog and/or digital, or any combinationthereof; and the facilities used may be private, public, third-partyprovided, or any combination thereof, without limitation.

Primary Data and Exemplary Primary Storage Devices

Primary data 112 according to some embodiments is production data orother “live” data generated by the operating system and/or applications110 operating on a client computing device 102. The primary data 112 isgenerally stored on the primary storage device(s) 104 and is organizedvia a file system supported by the client computing device 102. Forinstance, the client computing device(s) 102 and correspondingapplications 110 may create, access, modify, write, delete, andotherwise use primary data 112. In some cases, some or all of theprimary data 112 can be stored in cloud storage resources (e.g., primarystorage device 104 may be a cloud-based resource).

Primary data 112 is generally in the native format of the sourceapplication 110. According to certain aspects, primary data 112 is aninitial or first (e.g., created before any other copies or before atleast one other copy) stored copy of data generated by the sourceapplication 110. Primary data 112 in some cases is created substantiallydirectly from data generated by the corresponding source applications110.

The primary storage devices 104 storing the primary data 112 may berelatively fast and/or expensive technology (e.g., a disk drive, ahard-disk array, solid state memory, etc.). In addition, primary data112 may be highly changeable and/or may be intended for relatively shortterm retention (e.g., hours, days, or weeks).

According to some embodiments, the client computing device 102 canaccess primary data 112 from the primary storage device 104 by makingconventional file system calls via the operating system. Primary data112 may include structured data (e.g., database files), unstructureddata (e.g., documents), and/or semi-structured data. Some specificexamples are described below with respect to FIG. 1B.

It can be useful in performing certain tasks to organize the primarydata 112 into units of different granularities. In general, primary data112 can include files, directories, file system volumes, data blocks,extents, or any other hierarchies or organizations of data objects. Asused herein, a “data object” can refer to both (1) any file that iscurrently addressable by a file system or that was previouslyaddressable by the file system (e.g., an archive file) and (2) a subsetof such a file (e.g., a data block).

As will be described in further detail, it can also be useful inperforming certain functions of the information management system 100 toaccess and modify metadata within the primary data 112. Metadatagenerally includes information about data objects or characteristicsassociated with the data objects. For simplicity herein, it is to beunderstood that, unless expressly stated otherwise, any reference toprimary data 112 generally also includes its associated metadata, butreferences to the metadata do not include the primary data.

Metadata can include, without limitation, one or more of the following:the data owner (e.g., the client or user that generates the data), thelast modified time (e.g., the time of the most recent modification ofthe data object), a data object name (e.g., a file name), a data objectsize (e.g., a number of bytes of data), information about the content(e.g., an indication as to the existence of a particular search term),user-supplied tags, to/from information for email (e.g., an emailsender, recipient, etc.), creation date, file type (e.g., format orapplication type), last accessed time, application type (e.g., type ofapplication that generated the data object), location/network (e.g., acurrent, past or future location of the data object and network pathwaysto/from the data object), geographic location (e.g., GPS coordinates),frequency of change (e.g., a period in which the data object ismodified), business unit (e.g., a group or department that generates,manages or is otherwise associated with the data object), aginginformation (e.g., a schedule, such as a time period, in which the dataobject is migrated to secondary or long term storage), boot sectors,partition layouts, file location within a file folder directorystructure, user permissions, owners, groups, access control lists[ACLs]), system metadata (e.g., registry information), combinations ofthe same or other similar information related to the data object.

In addition to metadata generated by or related to file systems andoperating systems, some of the applications 110 and/or other componentsof the information management system 100 maintain indices of metadatafor data objects, e.g., metadata associated with individual emailmessages. Thus, each data object may be associated with correspondingmetadata. The use of metadata to perform classification and otherfunctions is described in greater detail below.

Each of the client computing devices 102 are generally associated withand/or in communication with one or more of the primary storage devices104 storing corresponding primary data 112. A client computing device102 may be considered to be “associated with” or “in communication with”a primary storage device 104 if it is capable of one or more of: routingand/or storing data (e.g., primary data 112) to the particular primarystorage device 104, coordinating the routing and/or storing of data tothe particular primary storage device 104, retrieving data from theparticular primary storage device 104, coordinating the retrieval ofdata from the particular primary storage device 104, and modifyingand/or deleting data retrieved from the particular primary storagedevice 104.

The primary storage devices 104 can include any of the different typesof storage devices described above, or some other kind of suitablestorage device. The primary storage devices 104 may have relatively fastI/O times and/or are relatively expensive in comparison to the secondarystorage devices 108. For example, the information management system 100may generally regularly access data and metadata stored on primarystorage devices 104, whereas data and metadata stored on the secondarystorage devices 108 is accessed relatively less frequently.

Primary storage device 104 may be dedicated or shared. In some cases,each primary storage device 104 is dedicated to an associated clientcomputing device 102. For instance, a primary storage device 104 in oneembodiment is a local disk drive of a corresponding client computingdevice 102. In other cases, one or more primary storage devices 104 canbe shared by multiple client computing devices 102, e.g., via a networksuch as in a cloud storage implementation. As one example, a primarystorage device 104 can be a disk array shared by a group of clientcomputing devices 102, such as one of the following types of diskarrays: EMC Clariion, EMC Symmetrix, EMC Celerra, Dell EqualLogic, IBMXIV, NetApp FAS, HP EVA, and HP 3PAR.

The information management system 100 may also include hosted services(not shown), which may be hosted in some cases by an entity other thanthe organization that employs the other components of the informationmanagement system 100. For instance, the hosted services may be providedby various online service providers to the organization. Such serviceproviders can provide services including social networking services,hosted email services, or hosted productivity applications or otherhosted applications). Hosted services may include software-as-a-service(SaaS), platform-as-a-service (PaaS), application service providers(ASPs), cloud services, or other mechanisms for delivering functionalityvia a network. As it provides services to users, each hosted service maygenerate additional data and metadata under management of theinformation management system 100, e.g., as primary data 112. In somecases, the hosted services may be accessed using one of the applications110. As an example, a hosted mail service may be accessed via browserrunning on a client computing device 102. The hosted services may beimplemented in a variety of computing environments. In some cases, theyare implemented in an environment having a similar arrangement to theinformation management system 100, where various physical and logicalcomponents are distributed over a network.

Secondary Copies and Exemplary Secondary Storage Devices

The primary data 112 stored on the primary storage devices 104 may becompromised in some cases, such as when an employee deliberately oraccidentally deletes or overwrites primary data 112 during their normalcourse of work. Or the primary storage devices 104 can be damaged, lost,or otherwise corrupted. For recovery and/or regulatory compliancepurposes, it is therefore useful to generate copies of the primary data112. Accordingly, the information management system 100 includes one ormore secondary storage computing devices 106 and one or more secondarystorage devices 108 configured to create and store one or more secondarycopies 116 of the primary data 112 and associated metadata. Thesecondary storage computing devices 106 and the secondary storagedevices 108 may sometimes be referred to as a secondary storagesubsystem 118.

Creation of secondary copies 116 can help in search and analysis effortsand meet other information management goals, such as: restoring dataand/or metadata if an original version (e.g., of primary data 112) islost (e.g., by deletion, corruption, or disaster); allowingpoint-in-time recovery; complying with regulatory data retention andelectronic discovery (e-discovery) requirements; reducing utilizedstorage capacity; facilitating organization and search of data;improving user access to data files across multiple computing devicesand/or hosted services; and implementing data retention policies.

The client computing devices 102 access or receive primary data 112 andcommunicate the data, e.g., over one or more communication pathways 114,for storage in the secondary storage device(s) 108.

A secondary copy 116 can comprise a separate stored copy of applicationdata that is derived from one or more earlier-created, stored copies(e.g., derived from primary data 112 or another secondary copy 116).Secondary copies 116 can include point-in-time data, and may be intendedfor relatively long-term retention (e.g., weeks, months or years),before some or all of the data is moved to other storage or isdiscarded.

In some cases, a secondary copy 116 is a copy of application datacreated and stored subsequent to at least one other stored instance(e.g., subsequent to corresponding primary data 112 or to anothersecondary copy 116), in a different storage device than at least oneprevious stored copy, and/or remotely from at least one previous storedcopy. In some other cases, secondary copies can be stored in the samestorage device as primary data 112 and/or other previously storedcopies. For example, in one embodiment a disk array capable ofperforming hardware snapshots stores primary data 112 and creates andstores hardware snapshots of the primary data 112 as secondary copies116. Secondary copies 116 may be stored in relatively slow and/or lowcost storage (e.g., magnetic tape). A secondary copy 116 may be storedin a backup or archive format, or in some other format different thanthe native source application format or other primary data format.

In some cases, secondary copies 116 are indexed so users can browse andrestore at another point in time. After creation of a secondary copy 116representative of certain primary data 112, a pointer or other locationindicia (e.g., a stub) may be placed in primary data 112, or beotherwise associated with primary data 112 to indicate the currentlocation on the secondary storage device(s) 108 of secondary copy 116.

Since an instance of a data object or metadata in primary data 112 maychange over time as it is modified by an application 110 (or hostedservice or the operating system), the information management system 100may create and manage multiple secondary copies 116 of a particular dataobject or metadata, each representing the state of the data object inprimary data 112 at a particular point in time. Moreover, since aninstance of a data object in primary data 112 may eventually be deletedfrom the primary storage device 104 and the file system, the informationmanagement system 100 may continue to manage point-in-timerepresentations of that data object, even though the instance in primarydata 112 no longer exists.

For virtualized computing devices the operating system and otherapplications 110 of the client computing device(s) 102 may executewithin or under the management of virtualization software (e.g., a VMM),and the primary storage device(s) 104 may comprise a virtual diskcreated on a physical storage device. The information management system100 may create secondary copies 116 of the files or other data objectsin a virtual disk file and/or secondary copies 116 of the entire virtualdisk file itself (e.g., of an entire .vmdk file).

Secondary copies 116 may be distinguished from corresponding primarydata 112 in a variety of ways, some of which will now be described.First, as discussed, secondary copies 116 can be stored in a differentformat (e.g., backup, archive, or other non-native format) than primarydata 112. For this or other reasons, secondary copies 116 may not bedirectly useable by the applications 110 of the client computing device102, e.g., via standard system calls or otherwise without modification,processing, or other intervention by the information management system100.

Secondary copies 116 are also in some embodiments stored on a secondarystorage device 108 that is inaccessible to the applications 110 runningon the client computing devices 102 (and/or hosted services). Somesecondary copies 116 may be “offline copies,” in that they are notreadily available (e.g., not mounted to tape or disk). Offline copiescan include copies of data that the information management system 100can access without human intervention (e.g., tapes within an automatedtape library, but not yet mounted in a drive), and copies that theinformation management system 100 can access only with at least somehuman intervention (e.g., tapes located at an offsite storage site).

The Use of Intermediate Devices for Creating Secondary Copies

Creating secondary copies can be a challenging task. For instance, therecan be hundreds or thousands of client computing devices 102 continuallygenerating large volumes of primary data 112 to be protected. Also,there can be significant overhead involved in the creation of secondarycopies 116. Moreover, secondary storage devices 108 may be specialpurpose components, and interacting with them can require specializedintelligence.

In some cases, the client computing devices 102 interact directly withthe secondary storage device 108 to create the secondary copies 116.However, in view of the factors described above, this approach cannegatively impact the ability of the client computing devices 102 toserve the applications 110 and produce primary data 112. Further, theclient computing devices 102 may not be optimized for interaction withthe secondary storage devices 108.

Thus, in some embodiments, the information management system 100includes one or more software and/or hardware components which generallyact as intermediaries between the client computing devices 102 and thesecondary storage devices 108. In addition to off-loading certainresponsibilities from the client computing devices 102, theseintermediate components can provide other benefits. For instance, asdiscussed further below with respect to FIG. 1D, distributing some ofthe work involved in creating secondary copies 116 can enhancescalability.

The intermediate components can include one or more secondary storagecomputing devices 106 as shown in FIG. 1A and/or one or more mediaagents, which can be software modules operating on correspondingsecondary storage computing devices 106 (or other appropriate computingdevices). Media agents are discussed below (e.g., with respect to FIGS.1C-1E).

The secondary storage computing device(s) 106 can comprise any of thecomputing devices described above, without limitation. In some cases,the secondary storage computing device(s) 106 include specializedhardware and/or software componentry for interacting with the secondarystorage devices 108.

To create a secondary copy 116 involving the copying of data from theprimary storage subsystem 117 to the secondary storage subsystem 118,the client computing device 102 in some embodiments communicates theprimary data 112 to be copied (or a processed version thereof) to thedesignated secondary storage computing device 106, via the communicationpathway 114. The secondary storage computing device 106 in turn conveysthe received data (or a processed version thereof) to the secondarystorage device 108. In some such configurations, the communicationpathway 114 between the client computing device 102 and the secondarystorage computing device 106 comprises a portion of a LAN, WAN or SAN.In other cases, at least some client computing devices 102 communicatedirectly with the secondary storage devices 108 (e.g., via Fibre Channelor SCSI connections). In some other cases, one or more secondary copies116 are created from existing secondary copies, such as in the case ofan auxiliary copy operation, described in greater detail below.

Exemplary Primary Data and an Exemplary Secondary Copy

FIG. 1B is a detailed view showing some specific examples of primarydata stored on the primary storage device(s) 104 and secondary copy datastored on the secondary storage device(s) 108, with other components inthe system removed for the purposes of illustration. Stored on theprimary storage device(s) 104 are primary data objects including wordprocessing documents 119A-B, spreadsheets 120, presentation documents122, video files 124, image files 126, email mailboxes 128 (andcorresponding email messages 129A-C), html/xml or other types of markuplanguage files 130, databases 132 and corresponding tables or other datastructures 133A-133C).

Some or all primary data objects are associated with correspondingmetadata (e.g., “Meta1-11”), which may include file system metadataand/or application specific metadata. Stored on the secondary storagedevice(s) 108 are secondary copy data objects 134A-C which may includecopies of or otherwise represent corresponding primary data objects andmetadata.

As shown, the secondary copy data objects 134A-C can individuallyrepresent more than one primary data object. For example, secondary copydata object 134A represents three separate primary data objects 133C,122, and 129C (represented as 133C′, 122′, and 129C′, respectively, andaccompanied by the corresponding metadata Meta11, Meta3, and Meta8,respectively). Moreover, as indicated by the prime mark (′), a secondarycopy object may store a representation of a primary data object and/ormetadata differently than the original format, e.g., in a compressed,encrypted, deduplicated, or other modified format. Likewise, secondarydata object 134B represents primary data objects 120, 133B, and 119A as120′, 133B′, and 119A′, respectively and accompanied by correspondingmetadata Meta2, Meta10, and Meta1, respectively. Also, secondary dataobject 134C represents primary data objects 133A, 1196, and 129A as133A′, 119B′, and 129A′, respectively, accompanied by correspondingmetadata Meta9, Meta5, and Meta6, respectively.

Exemplary Information Management System Architecture

The information management system 100 can incorporate a variety ofdifferent hardware and software components, which can in turn beorganized with respect to one another in many different configurations,depending on the embodiment. There are critical design choices involvedin specifying the functional responsibilities of the components and therole of each component in the information management system 100. Forinstance, as will be discussed, such design choices can impactperformance as well as the adaptability of the information managementsystem 100 to data growth or other changing circumstances.

FIG. 1C shows an information management system 100 designed according tothese considerations and which includes: storage manager 140, acentralized storage and/or information manager that is configured toperform certain control functions, one or more data agents 142 executingon the client computing device(s) 102 configured to process primary data112, and one or more media agents 144 executing on the one or moresecondary storage computing devices 106 for performing tasks involvingthe secondary storage devices 108. While distributing functionalityamongst multiple computing devices can have certain advantages, in othercontexts it can be beneficial to consolidate functionality on the samecomputing device. As such, in various other embodiments, one or more ofthe components shown in FIG. 1C as being implemented on separatecomputing devices are implemented on the same computing device. In oneconfiguration, a storage manager 140, one or more data agents 142, andone or more media agents 144 are all implemented on the same computingdevice. In another embodiment, one or more data agents 142 and one ormore media agents 144 are implemented on the same computing device,while the storage manager 140 is implemented on a separate computingdevice, etc. without limitation.

Storage Manager

As noted, the number of components in the information management system100 and the amount of data under management can be quite large. Managingthe components and data is therefore a significant task, and a task thatcan grow in an often unpredictable fashion as the quantity of componentsand data scale to meet the needs of the organization. For these andother reasons, according to certain embodiments, responsibility forcontrolling the information management system 100, or at least asignificant portion of that responsibility, is allocated to the storagemanager 140. By distributing control functionality in this manner, thestorage manager 140 can be adapted independently according to changingcircumstances. Moreover, a computing device for hosting the storagemanager 140 can be selected to best suit the functions of the storagemanager 140. These and other advantages are described in further detailbelow with respect to FIG. 1D.

The storage manager 140 may be a software module or other application,which, in some embodiments operates in conjunction with one or moreassociated data structures, e.g., a dedicated database (e.g., managementdatabase 146). In some embodiments, storage manager 140 is a computingdevice comprising circuitry for executing computer instructions andperforms the functions described herein. The storage manager generallyinitiates, performs, coordinates and/or controls storage and otherinformation management operations performed by the informationmanagement system 100, e.g., to protect and control the primary data 112and secondary copies 116 of data and metadata. In general, storagemanager 100 may be said to manage information management system 100,which includes managing the constituent components, e.g., data agentsand media agents, etc.

As shown by the dashed arrowed lines 114 in FIG. 1C, the storage manager140 may communicate with and/or control some or all elements of theinformation management system 100, such as the data agents 142 and mediaagents 144. Thus, in certain embodiments, control information originatesfrom the storage manager 140 and status reporting is transmitted tostorage manager 140 by the various managed components, whereas payloaddata and payload metadata is generally communicated between the dataagents 142 and the media agents 144 (or otherwise between the clientcomputing device(s) 102 and the secondary storage computing device(s)106), e.g., at the direction of and under the management of the storagemanager 140. Control information can generally include parameters andinstructions for carrying out information management operations, suchas, without limitation, instructions to perform a task associated withan operation, timing information specifying when to initiate a taskassociated with an operation, data path information specifying whatcomponents to communicate with or access in carrying out an operation,and the like. Payload data, on the other hand, can include the actualdata involved in the storage operation, such as content data written toa secondary storage device 108 in a secondary copy operation. Payloadmetadata can include any of the types of metadata described herein, andmay be written to a storage device along with the payload content data(e.g., in the form of a header).

In other embodiments, some information management operations arecontrolled by other components in the information management system 100(e.g., the media agent(s) 144 or data agent(s) 142), instead of or incombination with the storage manager 140.

According to certain embodiments, the storage manager 140 provides oneor more of the following functions:

-   -   initiating execution of secondary copy operations;    -   managing secondary storage devices 108 and inventory/capacity of        the same;    -   reporting, searching, and/or classification of data in the        information management system 100;    -   allocating secondary storage devices 108 for secondary storage        operations;    -   monitoring completion of and providing status reporting related        to secondary storage operations;    -   tracking age information relating to secondary copies 116,        secondary storage devices 108, and comparing the age information        against retention guidelines;    -   tracking movement of data within the information management        system 100;    -   tracking logical associations between components in the        information management system 100;    -   protecting metadata associated with the information management        system 100; and    -   implementing operations management functionality.

The storage manager 140 may maintain a database 146 (or “storage managerdatabase 146” or “management database 146”) of management-related dataand information management policies 148. The database 146 may include amanagement index 150 (or “index 150”) or other data structure thatstores logical associations between components of the system, userpreferences and/or profiles (e.g., preferences regarding encryption,compression, or deduplication of primary or secondary copy data,preferences regarding the scheduling, type, or other aspects of primaryor secondary copy or other operations, mappings of particularinformation management users or user accounts to certain computingdevices or other components, etc.), management tasks, mediacontainerization, or other useful data. For example, the storage manager140 may use the index 150 to track logical associations between mediaagents 144 and secondary storage devices 108 and/or movement of datafrom primary storage devices 104 to secondary storage devices 108. Forinstance, the index 150 may store data associating a client computingdevice 102 with a particular media agent 144 and/or secondary storagedevice 108, as specified in an information management policy 148 (e.g.,a storage policy, which is defined in more detail below).

Administrators and other people may be able to configure and initiatecertain information management operations on an individual basis. Butwhile this may be acceptable for some recovery operations or otherrelatively less frequent tasks, it is often not workable forimplementing on-going organization-wide data protection and management.Thus, the information management system 100 may utilize informationmanagement policies 148 for specifying and executing informationmanagement operations (e.g., on an automated basis). Generally, aninformation management policy 148 can include a data structure or otherinformation source that specifies a set of parameters (e.g., criteriaand rules) associated with storage or other information managementoperations.

The storage manager database 146 may maintain the information managementpolicies 148 and associated data, although the information managementpolicies 148 can be stored in any appropriate location. For instance, aninformation management policy 148 such as a storage policy may be storedas metadata in a media agent database 152 or in a secondary storagedevice 108 (e.g., as an archive copy) for use in restore operations orother information management operations, depending on the embodiment.Information management policies 148 are described further below.

According to certain embodiments, the storage manager database 146comprises a relational database (e.g., an SQL database) for trackingmetadata, such as metadata associated with secondary copy operations(e.g., what client computing devices 102 and corresponding data wereprotected). This and other metadata may additionally be stored in otherlocations, such as at the secondary storage computing devices 106 or onthe secondary storage devices 108, allowing data recovery without theuse of the storage manager 140 in some cases.

As shown, the storage manager 140 may include a jobs agent 156, a userinterface 158, and a management agent 154, all of which may beimplemented as interconnected software modules or application programs.

The jobs agent 156 in some embodiments initiates, controls, and/ormonitors the status of some or all storage or other informationmanagement operations previously performed, currently being performed,or scheduled to be performed by the information management system 100.For instance, the jobs agent 156 may access information managementpolicies 148 to determine when and how to initiate and control secondarycopy and other information management operations, as will be discussedfurther.

The user interface 158 may include information processing and displaysoftware, such as a graphical user interface (“GUI”), an applicationprogram interface (“API”), or other interactive interface(s) throughwhich users and system processes can retrieve information about thestatus of information management operations (e.g., storage operations)or issue instructions to the information management system 100 and itsconstituent components. Via the user interface 158, users may optionallyissue instructions to the components in the information managementsystem 100 regarding performance of storage and recovery operations. Forexample, a user may modify a schedule concerning the number of pendingsecondary copy operations. As another example, a user may employ the GUIto view the status of pending storage operations or to monitor thestatus of certain components in the information management system 100(e.g., the amount of capacity left in a storage device).

An “information management cell” (or “storage operation cell” or “cell”)may generally include a logical and/or physical grouping of acombination of hardware and software components associated withperforming information management operations on electronic data,typically one storage manager 140 and at least one client computingdevice 102 (comprising data agent(s) 142) and at least one media agent144. For instance, the components shown in FIG. 1C may together form aninformation management cell. Multiple cells may be organizedhierarchically. With this configuration, cells may inherit propertiesfrom hierarchically superior cells or be controlled by other cells inthe hierarchy (automatically or otherwise). Alternatively, in someembodiments, cells may inherit or otherwise be associated withinformation management policies, preferences, information managementmetrics, or other properties or characteristics according to theirrelative position in a hierarchy of cells. Cells may also be delineatedand/or organized hierarchically according to function, geography,architectural considerations, or other factors useful or desirable inperforming information management operations. A first cell may representa geographic segment of an enterprise, such as a Chicago office, and asecond cell may represent a different geographic segment, such as a NewYork office. Other cells may represent departments within a particularoffice. Where delineated by function, a first cell may perform one ormore first types of information management operations (e.g., one or morefirst types of secondary or other copies), and a second cell may performone or more second types of information management operations (e.g., oneor more second types of secondary or other copies).

The storage manager 140 may also track information that permits it toselect, designate, or otherwise identify content indices, deduplicationdatabases, or similar databases or resources or data sets within itsinformation management cell (or another cell) to be searched in responseto certain queries. Such queries may be entered by the user viainteraction with the user interface 158. In general, the managementagent 154 allows multiple information management cells to communicatewith one another. For example, the information management system 100 insome cases may be one information management cell of a network ofmultiple cells adjacent to one another or otherwise logically related ina WAN or LAN. With this arrangement, the cells may be connected to oneanother through respective management agents 154.

For instance, the management agent 154 can provide the storage manager140 with the ability to communicate with other components within theinformation management system 100 (and/or other cells within a largerinformation management system) via network protocols and applicationprogramming interfaces (“APIs”) including, e.g., HTTP, HTTPS, FTP, REST,virtualization software APIs, cloud service provider APIs, and hostedservice provider APIs. Inter-cell communication and hierarchy isdescribed in greater detail in e.g., U.S. Pat. Nos. 7,747,579 and7,343,453, which are incorporated by reference herein.

Data Agents

As discussed, a variety of different types of applications 110 canoperate on a given client computing device 102, including operatingsystems, database applications, e-mail applications, and virtualmachines, just to name a few. And, as part of the process of creatingand restoring secondary copies 116, the client computing devices 102 maybe tasked with processing and preparing the primary data 112 from thesevarious different applications 110. Moreover, the nature of theprocessing/preparation can differ across clients and application types,e.g., due to inherent structural and formatting differences amongapplications 110.

The one or more data agent(s) 142 are therefore advantageouslyconfigured in some embodiments to assist in the performance ofinformation management operations based on the type of data that isbeing protected, at a client-specific and/or application-specific level.

The data agent 142 may be a software module or component that isgenerally responsible for managing, initiating, or otherwise assistingin the performance of information management operations in informationmanagement system 100, generally as directed by storage manager 140. Forinstance, the data agent 142 may take part in performing data storageoperations such as the copying, archiving, migrating, and/or replicatingof primary data 112 stored in the primary storage device(s) 104. Thedata agent 142 may receive control information from the storage manager140, such as commands to transfer copies of data objects, metadata, andother payload data to the media agents 144.

In some embodiments, a data agent 142 may be distributed between theclient computing device 102 and storage manager 140 (and any otherintermediate components) or may be deployed from a remote location orits functions approximated by a remote process that performs some or allof the functions of data agent 142. In addition, a data agent 142 mayperform some functions provided by a media agent 144, or may performother functions such as encryption and deduplication.

As indicated, each data agent 142 may be specialized for a particularapplication 110, and the system can employ multiple application-specificdata agents 142, each of which may perform information managementoperations (e.g., perform backup, migration, and data recovery)associated with a different application 110. For instance, differentindividual data agents 142 may be designed to handle Microsoft Exchangedata, Lotus Notes data, Microsoft Windows file system data, MicrosoftActive Directory Objects data, SQL Server data, SharePoint data, Oracledatabase data, SAP database data, virtual machines and/or associateddata, and other types of data.

A file system data agent, for example, may handle data files and/orother file system information. If a client computing device 102 has twoor more types of data, a specialized data agent 142 may be used for eachdata type to copy, archive, migrate, and restore the client computingdevice 102 data. For example, to backup, migrate, and/or restore all ofthe data on a Microsoft Exchange server, the client computing device 102may use a Microsoft Exchange Mailbox data agent 142 to back up theExchange mailboxes, a Microsoft Exchange Database data agent 142 to backup the Exchange databases, a Microsoft Exchange Public Folder data agent142 to back up the Exchange Public Folders, and a Microsoft Windows FileSystem data agent 142 to back up the file system of the client computingdevice 102. In such embodiments, these specialized data agents 142 maybe treated as four separate data agents 142 even though they operate onthe same client computing device 102.

Other embodiments may employ one or more generic data agents 142 thatcan handle and process data from two or more different applications 110,or that can handle and process multiple data types, instead of or inaddition to using specialized data agents 142. For example, one genericdata agent 142 may be used to back up, migrate and restore MicrosoftExchange Mailbox data and Microsoft Exchange Database data while anothergeneric data agent may handle Microsoft Exchange Public Folder data andMicrosoft Windows File System data.

Each data agent 142 may be configured to access data and/or metadatastored in the primary storage device(s) 104 associated with the dataagent 142 and process the data as appropriate. For example, during asecondary copy operation, the data agent 142 may arrange or assemble thedata and metadata into one or more files having a certain format (e.g.,a particular backup or archive format) before transferring the file(s)to a media agent 144 or other component. The file(s) may include a listof files or other metadata. Each data agent 142 can also assist inrestoring data or metadata to primary storage devices 104 from asecondary copy 116. For instance, the data agent 142 may operate inconjunction with the storage manager 140 and one or more of the mediaagents 144 to restore data from secondary storage device(s) 108.

Media Agents

As indicated above with respect to FIG. 1A, off-loading certainresponsibilities from the client computing devices 102 to intermediatecomponents such as the media agent(s) 144 can provide a number ofbenefits including improved client computing device 102 operation,faster secondary copy operation performance, and enhanced scalability.In one specific example which will be discussed below in further detail,the media agent 144 can act as a local cache of copied data and/ormetadata that it has stored to the secondary storage device(s) 108,providing improved restore capabilities.

Generally speaking, a media agent 144 may be implemented as a softwaremodule that manages, coordinates, and facilitates the transmission ofdata, as directed by the storage manager 140, between a client computingdevice 102 and one or more secondary storage devices 108. Whereas thestorage manager 140 controls the operation of the information managementsystem 100, the media agent 144 generally provides a portal to secondarystorage devices 108. For instance, other components in the systeminteract with the media agents 144 to gain access to data stored on thesecondary storage devices 108, whether it be for the purposes ofreading, writing, modifying, or deleting data. Moreover, as will bedescribed further, media agents 144 can generate and store informationrelating to characteristics of the stored data and/or metadata, or cangenerate and store other types of information that generally providesinsight into the contents of the secondary storage devices 108.

Media agents 144 can comprise separate nodes in the informationmanagement system 100 (e.g., nodes that are separate from the clientcomputing devices 102, storage manager 140, and/or secondary storagedevices 108). In general, a node within the information managementsystem 100 can be a logically and/or physically separate component, andin some cases is a component that is individually addressable orotherwise identifiable. In addition, each media agent 144 may operate ona dedicated secondary storage computing device 106 in some cases, whilein other embodiments a plurality of media agents 144 operate on the samesecondary storage computing device 106.

A media agent 144 (and corresponding media agent database 152) may beconsidered to be “associated with” a particular secondary storage device108 if that media agent 144 is capable of one or more of: routing and/orstoring data to the particular secondary storage device 108,coordinating the routing and/or storing of data to the particularsecondary storage device 108, retrieving data from the particularsecondary storage device 108, coordinating the retrieval of data from aparticular secondary storage device 108, and modifying and/or deletingdata retrieved from the particular secondary storage device 108.

While media agent(s) 144 are generally associated with one or moresecondary storage devices 108, one or more media agents 144 in certainembodiments are physically separate from the secondary storage devices108. For instance, the media agents 144 may operate on secondary storagecomputing devices 106 having different housings or packages than thesecondary storage devices 108. In one example, a media agent 144operates on a first server computer and is in communication with asecondary storage device(s) 108 operating in a separate, rack-mountedRAID-based system.

Where the information management system 100 includes multiple mediaagents 144 (see, e.g., FIG. 1D), a first media agent 144 may providefailover functionality for a second, failed media agent 144. Inaddition, media agents 144 can be dynamically selected for storageoperations to provide load balancing. Failover and load balancing aredescribed in greater detail below.

In operation, a media agent 144 associated with a particular secondarystorage device 108 may instruct the secondary storage device 108 toperform an information management operation. For instance, a media agent144 may instruct a tape library to use a robotic arm or other retrievalmeans to load or eject a certain storage media, and to subsequentlyarchive, migrate, or retrieve data to or from that media, e.g., for thepurpose of restoring the data to a client computing device 102. Asanother example, a secondary storage device 108 may include an array ofhard disk drives or solid state drives organized in a RAIDconfiguration, and the media agent 144 may forward a logical unit number(LUN) and other appropriate information to the array, which uses thereceived information to execute the desired storage operation. The mediaagent 144 may communicate with a secondary storage device 108 via asuitable communications link, such as a SCSI or Fiber Channel link.

As shown, each media agent 144 may maintain an associated media agentdatabase 152. The media agent database 152 may be stored in a disk orother storage device (not shown) that is local to the secondary storagecomputing device 106 on which the media agent 144 operates. In othercases, the media agent database 152 is stored remotely from thesecondary storage computing device 106.

The media agent database 152 can include, among other things, an index153 (see, e.g., FIG. 1C), which comprises information generated duringsecondary copy operations and other storage or information managementoperations. The index 153 provides a media agent 144 or other componentwith a fast and efficient mechanism for locating secondary copies 116 orother data stored in the secondary storage devices 108. In some cases,the index 153 does not form a part of and is instead separate from themedia agent database 152.

A media agent index 153 or other data structure associated with theparticular media agent 144 may include information about the storeddata. For instance, for each secondary copy 116, the index 153 mayinclude metadata such as a list of the data objects (e.g.,files/subdirectories, database objects, mailbox objects, etc.), a pathto the secondary copy 116 on the corresponding secondary storage device108, location information indicating where the data objects are storedin the secondary storage device 108, when the data objects were createdor modified, etc. Thus, the index 153 includes metadata associated withthe secondary copies 116 that is readily available for use withouthaving to be first retrieved from the secondary storage device 108. Inyet further embodiments, some or all of the information in index 153 mayinstead or additionally be stored along with the secondary copies ofdata in a secondary storage device 108. In some embodiments, thesecondary storage devices 108 can include sufficient information toperform a “bare metal restore”, where the operating system of a failedclient computing device 102 or other restore target is automaticallyrebuilt as part of a restore operation.

Because the index 153 maintained in the media agent database 152 mayoperate as a cache, it can also be referred to as “an index cache.” Insuch cases, information stored in the index cache 153 typicallycomprises data that reflects certain particulars about storageoperations that have occurred relatively recently. After some triggeringevent, such as after a certain period of time elapses, or the indexcache 153 reaches a particular size, the index cache 153 may be copiedor migrated to a secondary storage device(s) 108. This information mayneed to be retrieved and uploaded back into the index cache 153 orotherwise restored to a media agent 144 to facilitate retrieval of datafrom the secondary storage device(s) 108. In some embodiments, thecached information may include format or containerization informationrelated to archives or other files stored on the storage device(s) 108.In this manner, the index cache 153 allows for accelerated restores.

In some alternative embodiments the media agent 144 generally acts as acoordinator or facilitator of storage operations between clientcomputing devices 102 and corresponding secondary storage devices 108,but does not actually write the data to the secondary storage device108. For instance, the storage manager 140 (or the media agent 144) mayinstruct a client computing device 102 and secondary storage device 108to communicate with one another directly. In such a case the clientcomputing device 102 transmits the data directly or via one or moreintermediary components to the secondary storage device 108 according tothe received instructions, and vice versa. In some such cases, the mediaagent 144 may still receive, process, and/or maintain metadata relatedto the storage operations. Moreover, in these embodiments, the payloaddata can flow through the media agent 144 for the purposes of populatingthe index cache 153 maintained in the media agent database 152, but notfor writing to the secondary storage device 108.

The media agent 144 and/or other components such as the storage manager140 may in some cases incorporate additional functionality, such as dataclassification, content indexing, deduplication, encryption,compression, and the like. Further details regarding these and otherfunctions are described below.

Distributed, Scalable Architecture

As described, certain functions of the information management system 100can be distributed amongst various physical and/or logical components inthe system. For instance, one or more of the storage manager 140, dataagents 142, and media agents 144 may operate on computing devices thatare physically separate from one another. This architecture can providea number of benefits.

For instance, hardware and software design choices for each distributedcomponent can be targeted to suit its particular function. The secondarycomputing devices 106 on which the media agents 144 operate can betailored for interaction with associated secondary storage devices 108and provide fast index cache operation, among other specific tasks.Similarly, the client computing device(s) 102 can be selected toeffectively service the applications 110 thereon, in order toefficiently produce and store primary data 112.

Moreover, in some cases, one or more of the individual components in theinformation management system 100 can be distributed to multiple,separate computing devices. As one example, for large file systems wherethe amount of data stored in the management database 146 is relativelylarge, the database 146 may be migrated to or otherwise reside on aspecialized database server (e.g., an SQL server) separate from a serverthat implements the other functions of the storage manager 140. Thisdistributed configuration can provide added protection because thedatabase 146 can be protected with standard database utilities (e.g.,SQL log shipping or database replication) independent from otherfunctions of the storage manager 140. The database 146 can beefficiently replicated to a remote site for use in the event of adisaster or other data loss at the primary site. Or the database 146 canbe replicated to another computing device within the same site, such asto a higher performance machine in the event that a storage manager hostdevice can no longer service the needs of a growing informationmanagement system 100.

The distributed architecture also provides both scalability andefficient component utilization. FIG. 1D shows an embodiment of theinformation management system 100 including a plurality of clientcomputing devices 102 and associated data agents 142 as well as aplurality of secondary storage computing devices 106 and associatedmedia agents 144.

Additional components can be added or subtracted based on the evolvingneeds of the information management system 100. For instance, dependingon where bottlenecks are identified, administrators can add additionalclient computing devices 102, secondary storage computing devices 106(and corresponding media agents 144), and/or secondary storage devices108. Moreover, where multiple fungible components are available, loadbalancing can be implemented to dynamically address identifiedbottlenecks. As an example, the storage manager 140 may dynamicallyselect which media agents 144 and/or secondary storage devices 108 touse for storage operations based on a processing load analysis of themedia agents 144 and/or secondary storage devices 108, respectively.

Moreover, each client computing device 102 in some embodiments cancommunicate with, among other components, any of the media agents 144,e.g., as directed by the storage manager 140. And each media agent 144may be able to communicate with, among other components, any of thesecondary storage devices 108, e.g., as directed by the storage manager140. Thus, operations can be routed to the secondary storage devices 108in a dynamic and highly flexible manner, to provide load balancing,failover, and the like. Further examples of scalable systems capable ofdynamic storage operations, and of systems capable of performing loadbalancing and fail over are provided in U.S. Pat. No. 7,246,207, whichis incorporated by reference herein.

In alternative configurations, certain components are not distributedand may instead reside and execute on the same computing device. Forexample, in some embodiments, one or more data agents 142 and thestorage manager 140 operate on the same client computing device 102. Inanother embodiment, one or more data agents 142 and one or more mediaagents 144 operate on a single computing device.

Exemplary Types of Information Management Operations

In order to protect and leverage stored data, the information managementsystem 100 can be configured to perform a variety of informationmanagement operations. As will be described, these operations cangenerally include secondary copy and other data movement operations,processing and data manipulation operations, analysis, reporting, andmanagement operations. The operations described herein may be performedon any type of computing device, e.g., between two computers connectedvia a LAN, to a mobile client telecommunications device connected to aserver via a WLAN, to any manner of client computing device coupled to acloud storage target, etc., without limitation.

Data Movement Operations

Data movement operations according to certain embodiments are generallyoperations that involve the copying or migration of data (e.g., payloaddata) between different locations in the information management system100 in an original/native and/or one or more different formats. Forexample, data movement operations can include operations in which storeddata is copied, migrated, or otherwise transferred from one or morefirst storage devices to one or more second storage devices, such asfrom primary storage device(s) 104 to secondary storage device(s) 108,from secondary storage device(s) 108 to different secondary storagedevice(s) 108, from secondary storage devices 108 to primary storagedevices 104, or from primary storage device(s) 104 to different primarystorage device(s) 104.

Data movement operations can include by way of example, backupoperations, archive operations, information lifecycle managementoperations such as hierarchical storage management operations,replication operations (e.g., continuous data replication operations),snapshot operations, deduplication or single-instancing operations,auxiliary copy operations, and the like. As will be discussed, some ofthese operations involve the copying, migration or other movement ofdata, without actually creating multiple, distinct copies. Nonetheless,some or all of these operations are referred to as “copy” operations forsimplicity.

Backup Operations

A backup operation creates a copy of a version of data (e.g., one ormore files or other data units) in primary data 112 at a particularpoint in time. Each subsequent backup copy may be maintainedindependently of the first. Further, a backup copy in some embodimentsis generally stored in a form that is different than the native format,e.g., a backup format. This can be in contrast to the version in primarydata 112 from which the backup copy is derived, and which may instead bestored in a native format of the source application(s) 110. In variouscases, backup copies can be stored in a format in which the data iscompressed, encrypted, deduplicated, and/or otherwise modified from theoriginal application format. For example, a backup copy may be stored ina backup format that facilitates compression and/or efficient long-termstorage.

Backup copies can have relatively long retention periods as compared toprimary data 112, and may be stored on media with slower retrieval timesthan primary data 112 and certain other types of secondary copies 116.On the other hand, backups may have relatively shorter retention periodsthan some other types of secondary copies 116, such as archive copies(described below). Backups may sometimes be stored at an offsitelocation.

Backup operations can include full backups, differential backups,incremental backups, “synthetic full” backups, and/or creating a“reference copy.” A full backup (or “standard full backup”) in someembodiments is generally a complete image of the data to be protected.However, because full backup copies can consume a relatively largeamount of storage, it can be useful to use a full backup copy as abaseline and only store changes relative to the full backup copy forsubsequent backup copies.

For instance, a differential backup operation (or cumulative incrementalbackup operation) tracks and stores changes that have occurred since thelast full backup. Differential backups can grow quickly in size, but canprovide relatively efficient restore times because a restore can becompleted in some cases using only the full backup copy and the latestdifferential copy.

An incremental backup operation generally tracks and stores changessince the most recent backup copy of any type, which can greatly reducestorage utilization. In some cases, however, restore times can berelatively long in comparison to full or differential backups becausecompleting a restore operation may involve accessing a full backup inaddition to multiple incremental backups.

Synthetic full backups generally consolidate data without directlybacking up data from the client computing device. A synthetic fullbackup is created from the most recent full backup (i.e., standard orsynthetic) and subsequent incremental and/or differential backups. Theresulting synthetic full backup is identical to what would have beencreated had the last backup for the subclient been a standard fullbackup. Unlike standard full, incremental, and differential backups, asynthetic full backup does not actually transfer data from a clientcomputer to the backup media, because it operates as a backupconsolidator. A synthetic full backup extracts the index data of eachparticipating subclient. Using this index data and the previously backedup user data images, it builds new full backup images, one for eachsubclient. The new backup images consolidate the index and user datastored in the related incremental, differential, and previous fullbackups, in some embodiments creating an archive file at the subclientlevel.

Any of the above types of backup operations can be at the volume-level,file-level, or block-level. Volume level backup operations generallyinvolve the copying of a data volume (e.g., a logical disk or partition)as a whole. In a file-level backup, the information management system100 may generally track changes to individual files, and includes copiesof files in the backup copy. In the case of a block-level backup, filesare broken into constituent blocks, and changes are tracked at theblock-level. Upon restore, the information management system 100reassembles the blocks into files in a transparent fashion.

Far less data may actually be transferred and copied to the secondarystorage devices 108 during a file-level copy than a volume-level copy.Likewise, a block-level copy may involve the transfer of less data thana file-level copy, resulting in faster execution times. However,restoring a relatively higher-granularity copy can result in longerrestore times. For instance, when restoring a block-level copy, theprocess of locating constituent blocks can sometimes result in longerrestore times as compared to file-level backups. Similar to backupoperations, the other types of secondary copy operations describedherein can also be implemented at either the volume-level, file-level,or block-level.

For example, in some embodiments, a reference copy may comprisecopy(ies) of selected objects from backed up data, typically to helporganize data by keeping contextual information from multiple sourcestogether, and/or help retain specific data for a longer period of time,such as for legal hold needs. A reference copy generally maintains dataintegrity, and when the data is restored, it may be viewed in the sameformat as the source data. In some embodiments, a reference copy isbased on a specialized client, individual subclient and associatedinformation management policies (e.g., storage policy, retention policy,etc.) that are administered within information management system 100.

Archive Operations

Because backup operations generally involve maintaining a version of thecopied data in primary data 112 and also maintaining backup copies insecondary storage device(s) 108, they can consume significant storagecapacity. To help reduce storage consumption, an archive operationaccording to certain embodiments creates a secondary copy 116 by bothcopying and removing source data. Or, seen another way, archiveoperations can involve moving some or all of the source data to thearchive destination. Thus, data satisfying criteria for removal (e.g.,data of a threshold age or size) may be removed from source storage. Thesource data may be primary data 112 or a secondary copy 116, dependingon the situation. As with backup copies, archive copies can be stored ina format in which the data is compressed, encrypted, deduplicated,and/or otherwise modified from the format of the original application orsource copy. In addition, archive copies may be retained for relativelylong periods of time (e.g., years) and, in some cases, are neverdeleted. Archive copies are generally retained for longer periods oftime than backup copies, for example. In certain embodiments, archivecopies may be made and kept for extended periods in order to meetcompliance regulations.

Moreover, when primary data 112 is archived, in some cases thecorresponding primary data 112 or a portion thereof is deleted whencreating the archive copy. Thus, archiving can serve the purpose offreeing up space in the primary storage device(s) 104 and easing thedemand on computational resources on client computing device 102.Similarly, when a secondary copy 116 is archived, the secondary copy 116may be deleted, and an archive copy can therefore serve the purpose offreeing up space in secondary storage device(s) 108. In contrast, sourcecopies often remain intact when creating backup copies. Examples ofcompatible data archiving operations are provided in U.S. Pat. No.7,107,298, which is incorporated by reference herein.

Snapshot Operations

Snapshot operations can provide a relatively lightweight, efficientmechanism for protecting data. From an end-user viewpoint, a snapshotmay be thought of as an “instant” image of the primary data 112 at agiven point in time, and may include state and/or status informationrelative to an application that creates/manages the primary data 112. Inone embodiment, a snapshot may generally capture the directory structureof an object in primary data 112 such as a file or volume or other dataset at a particular moment in time and may also preserve file attributesand contents. A snapshot in some cases is created relatively quickly,e.g., substantially instantly, using a minimum amount of file space, butmay still function as a conventional file system backup.

A “hardware snapshot” (or “hardware-based snapshot”) operation can be asnapshot operation where a target storage device (e.g., a primarystorage device 104 or a secondary storage device 108) performs thesnapshot operation in a self-contained fashion, substantiallyindependently, using hardware, firmware and/or software operating on thestorage device itself. For instance, the storage device may be capableof performing snapshot operations upon request, generally withoutintervention or oversight from any of the other components in theinformation management system 100. In this manner, hardware snapshotscan off-load other components of information management system 100 fromprocessing involved in snapshot creation and management.

A “software snapshot” (or “software-based snapshot”) operation, on theother hand, can be a snapshot operation in which one or more othercomponents in information management system 100 (e.g., client computingdevices 102, data agents 142, etc.) implement a software layer thatmanages the snapshot operation via interaction with the target storagedevice. For instance, the component executing the snapshot managementsoftware layer may derive a set of pointers and/or data that representsthe snapshot. The snapshot management software layer may then transmitthe same to the target storage device, along with appropriateinstructions for writing the snapshot.

Some types of snapshots do not actually create another physical copy ofall the data as it existed at the particular point in time, but maysimply create pointers that are able to map files and directories tospecific memory locations (e.g., to specific disk blocks) where the dataresides, as it existed at the particular point in time. For example, asnapshot copy may include a set of pointers derived from the file systemor from an application. In some other cases, the snapshot may be createdat the block-level, such that creation of the snapshot occurs withoutawareness of the file system. Each pointer points to a respective storeddata block, so that collectively, the set of pointers reflect thestorage location and state of the data object (e.g., file(s) orvolume(s) or data set(s)) at a particular point in time when thesnapshot copy was created.

An initial snapshot may use only a small amount of disk space needed torecord a mapping or other data structure representing or otherwisetracking the blocks that correspond to the current state of the filesystem. Additional disk space is usually required only when files anddirectories are modified later on. Furthermore, when files are modified,typically only the pointers which map to blocks are copied, not theblocks themselves. In some embodiments, for example in the case of“copy-on-write” snapshots, when a block changes in primary storage, theblock is copied to secondary storage or cached in primary storage beforethe block is overwritten in primary storage, and the pointer to thatblock is changed to reflect the new location of that block. The snapshotmapping of file system data may also be updated to reflect the changedblock(s) at that particular point in time. In some other cases, asnapshot includes a full physical copy of all or substantially all ofthe data represented by the snapshot. Further examples of snapshotoperations are provided in U.S. Pat. No. 7,529,782, which isincorporated by reference herein.

A snapshot copy in many cases can be made quickly and withoutsignificantly impacting primary computing resources because largeamounts of data need not be copied or moved. In some embodiments, asnapshot may exist as a virtual file system, parallel to the actual filesystem. Users in some cases gain read-only access to the record of filesand directories of the snapshot. By electing to restore primary data 112from a snapshot taken at a given point in time, users may also returnthe current file system to the state of the file system that existedwhen the snapshot was taken.

Replication Operations

Another type of secondary copy operation is a replication operation.Some types of secondary copies 116 are used to periodically captureimages of primary data 112 at particular points in time (e.g., backups,archives, and snapshots). However, it can also be useful for recoverypurposes to protect primary data 112 in a more continuous fashion, byreplicating the primary data 112 substantially as changes occur. In somecases a replication copy can be a mirror copy, for instance, wherechanges made to primary data 112 are mirrored or substantiallyimmediately copied to another location (e.g., to secondary storagedevice(s) 108). By copying each write operation to the replication copy,two storage systems are kept synchronized or substantially synchronizedso that they are virtually identical at approximately the same time.Where entire disk volumes are mirrored, however, mirroring can requiresignificant amount of storage space and utilizes a large amount ofprocessing resources.

According to some embodiments storage operations are performed onreplicated data that represents a recoverable state, or “known goodstate” of a particular application running on the source system. Forinstance, in certain embodiments, known good replication copies may beviewed as copies of primary data 112. This feature allows the system todirectly access, copy, restore, backup or otherwise manipulate thereplication copies as if the data were the “live” primary data 112. Thiscan reduce access time, storage utilization, and impact on sourceapplications 110, among other benefits. Based on known good stateinformation, the information management system 100 can replicatesections of application data that represent a recoverable state ratherthan rote copying of blocks of data. Examples of compatible replicationoperations (e.g., continuous data replication) are provided in U.S. Pat.No. 7,617,262, which is incorporated by reference herein.

Deduplication/Single-Instancing Operations

Another type of data movement operation is deduplication orsingle-instance storage, which is useful to reduce the amount ofnon-primary data. For instance, some or all of the above-describedsecondary storage operations can involve deduplication in some fashion.New data is read, broken down into portions (e.g., sub-file levelblocks, files, etc.) of a selected granularity, compared with blocksthat are already in secondary storage, and only the new blocks arestored. Blocks that already exist are represented as pointers to thealready stored data.

In order to streamline the comparison process, the informationmanagement system 100 may calculate and/or store signatures (e.g.,hashes or cryptographically unique IDs) corresponding to the individualdata blocks in a database and compare the signatures instead ofcomparing entire data blocks. In some cases, only a single instance ofeach element is stored, and deduplication operations may therefore bereferred to interchangeably as “single-instancing” operations. Dependingon the implementation, however, deduplication or single-instancingoperations can store more than one instance of certain data blocks, butnonetheless significantly reduce data redundancy. Depending on theembodiment, deduplication blocks can be of fixed or variable length.Using variable length blocks can provide enhanced deduplication byresponding to changes in the data stream, but can involve complexprocessing. In some cases, the information management system 100utilizes a technique for dynamically aligning deduplication blocks(e.g., fixed-length blocks) based on changing content in the datastream, as described in U.S. Pat. No. 8,364,652, which is incorporatedby reference herein.

The information management system 100 can perform deduplication in avariety of manners at a variety of locations in the informationmanagement system 100. For instance, in some embodiments, theinformation management system 100 implements “target-side” deduplicationby deduplicating data (e.g., secondary copies 116) stored in thesecondary storage devices 108. In some such cases, the media agents 144are generally configured to manage the deduplication process. Forinstance, one or more of the media agents 144 maintain a correspondingdeduplication database that stores deduplication information (e.g.,datablock signatures). Examples of such a configuration are provided inU.S. Pat. Pub. No. 2012/0150826, which is incorporated by referenceherein. Instead of or in combination with “target-side” deduplication,deduplication can also be performed on the “source-side” (or“client-side”), e.g., to reduce the amount of traffic between the mediaagents 144 and the client computing device(s) 102 and/or reduceredundant data stored in the primary storage devices 104. According tovarious implementations, one or more of the storage devices of thetarget-side and/or source-side of an operation can be cloud-basedstorage devices. Thus, the target-side and/or source-side deduplicationcan be cloud-based deduplication. In particular, as discussedpreviously, the storage manager 140 may communicate with othercomponents within the information management system 100 via networkprotocols and cloud service provider APIs to facilitate cloud-baseddeduplication/single instancing. Examples of such deduplicationtechniques are provided in U.S. Pat. Pub. No. 2012/0150818, which isincorporated by reference herein. Some other compatiblededuplication/single instancing techniques are described in U.S. Pat.Pub. Nos. 2006/0224846 and 2009/0319534, which are incorporated byreference herein.

Information Lifecycle Management and Hierarchical Storage ManagementOperations

In some embodiments, files and other data over their lifetime move frommore expensive, quick access storage to less expensive, slower accessstorage. Operations associated with moving data through various tiers ofstorage are sometimes referred to as information lifecycle management(ILM) operations.

One type of ILM operation is a hierarchical storage management (HSM)operation. A HSM operation is generally an operation for automaticallymoving data between classes of storage devices, such as betweenhigh-cost and low-cost storage devices. For instance, an HSM operationmay involve movement of data from primary storage devices 104 tosecondary storage devices 108, or between tiers of secondary storagedevices 108. With each tier, the storage devices may be progressivelyrelatively cheaper, have relatively slower access/restore times, etc.For example, movement of data between tiers may occur as data becomesless important over time.

In some embodiments, an HSM operation is similar to an archive operationin that creating an HSM copy may (though not always) involve deletingsome of the source data, e.g., according to one or more criteria relatedto the source data. For example, an HSM copy may include data fromprimary data 112 or a secondary copy 116 that is larger than a givensize threshold or older than a given age threshold and that is stored ina backup format.

Often, and unlike some types of archive copies, HSM data that is removedor aged from the source is replaced by a logical reference pointer orstub. The reference pointer or stub can be stored in the primary storagedevice 104 (or other source storage device, such as a secondary storagedevice 108) to replace the deleted source data and to point to orotherwise indicate the new location in a secondary storage device 108.

According to one example, files are generally moved between higher andlower cost storage depending on how often the files are accessed. When auser requests access to the HSM data that has been removed or migrated,the information management system 100 uses the stub to locate the dataand may make recovery of the data appear transparent, even though theHSM data may be stored at a location different from other source data.In this manner, the data appears to the user (e.g., in file systembrowsing windows and the like) as if it still resides in the sourcelocation (e.g., in a primary storage device 104). The stub may alsoinclude some metadata associated with the corresponding data, so that afile system and/or application can provide some information about thedata object and/or a limited-functionality version (e.g., a preview) ofthe data object.

An HSM copy may be stored in a format other than the native applicationformat (e.g., where the data is compressed, encrypted, deduplicated,and/or otherwise modified from the original native application format).In some cases, copies which involve the removal of data from sourcestorage and the maintenance of stub or other logical referenceinformation on source storage may be referred to generally as “on-linearchive copies”. On the other hand, copies which involve the removal ofdata from source storage without the maintenance of stub or otherlogical reference information on source storage may be referred to as“off-line archive copies”. Examples of HSM and ILM techniques areprovided in U.S. Pat. No. 7,343,453, which is incorporated by referenceherein.

Auxiliary Copy and Disaster Recovery Operations

An auxiliary copy is generally a copy operation in which a copy iscreated of an existing secondary copy 116. For instance, an initialsecondary copy 116 may be generated using or otherwise be derived fromprimary data 112 (or other data residing in the secondary storagesubsystem 118), whereas an auxiliary copy is generated from the initialsecondary copy 116. Auxiliary copies can be used to create additionalstandby copies of data and may reside on different secondary storagedevices 108 than the initial secondary copies 116. Thus, auxiliarycopies can be used for recovery purposes if initial secondary copies 116become unavailable. Exemplary compatible auxiliary copy techniques aredescribed in further detail in U.S. Pat. No. 8,230,195, which isincorporated by reference herein.

The information management system 100 may also perform disaster recoveryoperations that make or retain disaster recovery copies, often assecondary, high-availability disk copies. The information managementsystem 100 may create secondary disk copies and store the copies atdisaster recovery locations using auxiliary copy or replicationoperations, such as continuous data replication technologies. Dependingon the particular data protection goals, disaster recovery locations canbe remote from the client computing devices 102 and primary storagedevices 104, remote from some or all of the secondary storage devices108, or both.

Data Analysis, Reporting, and Management Operations

Data analysis, reporting, and management operations can be differentthan data movement operations in that they do not necessarily involvethe copying, migration or other transfer of data (e.g., primary data 112or secondary copies 116) between different locations in the system. Forinstance, data analysis operations may involve processing (e.g., offlineprocessing) or modification of already stored primary data 112 and/orsecondary copies 116. However, in some embodiments data analysisoperations are performed in conjunction with data movement operations.Some data analysis operations include content indexing operations andclassification operations which can be useful in leveraging the dataunder management to provide enhanced search and other features. Otherdata analysis operations such as compression and encryption can providedata reduction and security benefits, respectively.

Classification Operations/Content Indexing

In some embodiments, the information management system 100 analyzes andindexes characteristics, content, and metadata associated with theprimary data 112 and/or secondary copies 116. The content indexing canbe used to identify files or other data objects having pre-definedcontent (e.g., user-defined keywords or phrases, other keywords/phrasesthat are not defined by a user, etc.), and/or metadata (e.g., emailmetadata such as “to”, “from”, “cc”, “bcc”, attachment name, receivedtime, etc.).

The information management system 100 generally organizes and cataloguesthe results in a content index, which may be stored within the mediaagent database 152, for example. The content index can also include thestorage locations of (or pointer references to) the indexed data in theprimary data 112 or secondary copies 116, as appropriate. The resultsmay also be stored, in the form of a content index database orotherwise, elsewhere in the information management system 100 (e.g., inthe primary storage devices 104, or in the secondary storage device108). Such index data provides the storage manager 140 or anothercomponent with an efficient mechanism for locating primary data 112and/or secondary copies 116 of data objects that match particularcriteria.

For instance, search criteria can be specified by a user through userinterface 158 of the storage manager 140. In some cases, the informationmanagement system 100 analyzes data and/or metadata in secondary copies116 to create an “off-line” content index, without significantlyimpacting the performance of the client computing devices 102. Dependingon the embodiment, the system can also implement “on-line” contentindexing, e.g., of primary data 112. Examples of compatible contentindexing techniques are provided in U.S. Pat. No. 8,170,995, which isincorporated by reference herein.

One or more components can be configured to scan data and/or associatedmetadata for classification purposes to populate a database (or otherdata structure) of information, which can be referred to as a “dataclassification database” or a “metabase”. Depending on the embodiment,the data classification database(s) can be organized in a variety ofdifferent ways, including centralization, logical sub-divisions, and/orphysical sub-divisions. For instance, one or more centralized dataclassification databases may be associated with different subsystems ortiers within the information management system 100. As an example, theremay be a first centralized metabase associated with the primary storagesubsystem 117 and a second centralized metabase associated with thesecondary storage subsystem 118. In other cases, there may be one ormore metabases associated with individual components, e.g., clientcomputing devices 102 and/or media agents 144. In some embodiments, adata classification database (metabase) may reside as one or more datastructures within management database 146, or may be otherwiseassociated with storage manager 140.

In some cases, the metabase(s) may be included in separate database(s)and/or on separate storage device(s) from primary data 112 and/orsecondary copies 116, such that operations related to the metabase donot significantly impact performance on other components in theinformation management system 100. In other cases, the metabase(s) maybe stored along with primary data 112 and/or secondary copies 116. Filesor other data objects can be associated with identifiers (e.g., tagentries, etc.) in the media agent 144 (or other indices) to facilitatesearches of stored data objects. Among a number of other benefits, themetabase can also allow efficient, automatic identification of files orother data objects to associate with secondary copy or other informationmanagement operations (e.g., in lieu of scanning an entire file system).Examples of compatible metabases and data classification operations areprovided in U.S. Pat. Nos. 8,229,954 and 7,747,579, which areincorporated by reference herein.

Encryption Operations

The information management system 100 in some cases is configured toprocess data (e.g., files or other data objects, secondary copies 116,etc.), according to an appropriate encryption algorithm (e.g., Blowfish,Advanced Encryption Standard [AES], Triple Data Encryption Standard[3-DES], etc.) to limit access and provide data security in theinformation management system 100. The information management system 100in some cases encrypts the data at the client level, such that theclient computing devices 102 (e.g., the data agents 142) encrypt thedata prior to forwarding the data to other components, e.g., beforesending the data to media agents 144 during a secondary copy operation.In such cases, the client computing device 102 may maintain or haveaccess to an encryption key or passphrase for decrypting the data uponrestore. Encryption can also occur when creating copies of secondarycopies, e.g., when creating auxiliary copies or archive copies. In yetfurther embodiments, the secondary storage devices 108 can implementbuilt-in, high performance hardware encryption.

Management and Reporting Operations

Certain embodiments leverage the integrated, ubiquitous nature of theinformation management system 100 to provide useful system-widemanagement and reporting functions. Examples of some compatiblemanagement and reporting techniques are provided in U.S. Pat. No.7,343,453, which is incorporated by reference herein.

Operations management can generally include monitoring and managing thehealth and performance of information management system 100 by, withoutlimitation, performing error tracking, generating granularstorage/performance metrics (e.g., job success/failure information,deduplication efficiency, etc.), generating storage modeling and costinginformation, and the like. As an example, a storage manager 140 or othercomponent in the information management system 100 may analyze trafficpatterns and suggest and/or automatically route data via a particularroute to minimize congestion. In some embodiments, the system cangenerate predictions relating to storage operations or storage operationinformation. Such predictions, which may be based on a trendinganalysis, may predict various network operations or resource usage, suchas network traffic levels, storage media use, use of bandwidth ofcommunication links, use of media agent components, etc. Furtherexamples of traffic analysis, trend analysis, prediction generation, andthe like are described in U.S. Pat. No. 7,343,453, which is incorporatedby reference herein.

In some configurations, a master storage manager 140 may track thestatus of storage operation cells in a hierarchy, such as the status ofjobs, system components, system resources, and other items, bycommunicating with storage managers 140 (or other components) in therespective storage operation cells. Moreover, the master storage manager140 may track the status of its associated storage operation cells andinformation management operations by receiving periodic status updatesfrom the storage managers 140 (or other components) in the respectivecells regarding jobs, system components, system resources, and otheritems. In some embodiments, a master storage manager 140 may storestatus information and other information regarding its associatedstorage operation cells and other system information in its index 150(or other location).

The master storage manager 140 or other component may also determinewhether certain storage-related criteria or other criteria aresatisfied, and perform an action or trigger event (e.g., data migration)in response to the criteria being satisfied, such as where a storagethreshold is met for a particular volume, or where inadequate protectionexists for certain data. For instance, in some embodiments, data fromone or more storage operation cells is used to dynamically andautomatically mitigate recognized risks, and/or to advise users of risksor suggest actions to mitigate these risks. For example, an informationmanagement policy may specify certain requirements (e.g., that a storagedevice should maintain a certain amount of free space, that secondarycopies should occur at a particular interval, that data should be agedand migrated to other storage after a particular period, that data on asecondary volume should always have a certain level of availability andbe restorable within a given time period, that data on a secondaryvolume may be mirrored or otherwise migrated to a specified number ofother volumes, etc.). If a risk condition or other criterion istriggered, the system may notify the user of these conditions and maysuggest (or automatically implement) an action to mitigate or otherwiseaddress the risk. For example, the system may indicate that data from aprimary copy 112 should be migrated to a secondary storage device 108 tofree space on the primary storage device 104. Examples of the use ofrisk factors and other triggering criteria are described in U.S. Pat.No. 7,343,453, which is incorporated by reference herein.

In some embodiments, the system 100 may also determine whether a metricor other indication satisfies particular storage criteria and, if so,perform an action. For example, as previously described, a storagepolicy or other definition might indicate that a storage manager 140should initiate a particular action if a storage metric or otherindication drops below or otherwise fails to satisfy specified criteriasuch as a threshold of data protection. Examples of such metrics aredescribed in U.S. Pat. No. 7,343,453, which is incorporated by referenceherein.

In some embodiments, risk factors may be quantified into certainmeasurable service or risk levels for ease of comprehension. Forexample, certain applications and associated data may be considered tobe more important by an enterprise than other data and services.Financial compliance data, for example, may be of greater importancethan marketing materials, etc. Network administrators may assignpriority values or “weights” to certain data and/or applications,corresponding to the relative importance. The level of compliance ofstorage operations specified for these applications may also be assigneda certain value. Thus, the health, impact, and overall importance of aservice may be determined, such as by measuring the compliance value andcalculating the product of the priority value and the compliance valueto determine the “service level” and comparing it to certain operationalthresholds to determine whether it is acceptable. Further examples ofthe service level determination are provided in U.S. Pat. No. 7,343,453,which is incorporated by reference herein.

The system 100 may additionally calculate data costing and dataavailability associated with information management operation cellsaccording to an embodiment of the invention. For instance, data receivedfrom the cell may be used in conjunction with hardware-relatedinformation and other information about system elements to determine thecost of storage and/or the availability of particular data in thesystem. Exemplary information generated could include how fast aparticular department is using up available storage space, how long datawould take to recover over a particular system pathway from a particularsecondary storage device, costs over time, etc. Moreover, in someembodiments, such information may be used to determine or predict theoverall cost associated with the storage of certain information. Thecost associated with hosting a certain application may be based, atleast in part, on the type of media on which the data resides, forexample. Storage devices may be assigned to a particular costcategories, for example. Further examples of costing techniques aredescribed in U.S. Pat. No. 7,343,453, which is incorporated by referenceherein.

Any of the above types of information (e.g., information related totrending, predictions, job, cell or component status, risk, servicelevel, costing, etc.) can generally be provided to users via the userinterface 158 in a single, integrated view or console (not shown). Theconsole may support a reporting capability that allows for thegeneration of a variety of reports, which may be tailored to aparticular aspect of information management. Report types may include:scheduling, event management, media management and data aging. Availablereports may also include backup history, data aging history, auxiliarycopy history, job history, library and drive, media in library, restorehistory, and storage policy, etc., without limitation. Such reports maybe specified and created at a certain point in time as a systemanalysis, forecasting, or provisioning tool. Integrated reports may alsobe generated that illustrate storage and performance metrics, risks andstorage costing information. Moreover, users may create their ownreports based on specific needs.

The integrated user interface 158 can include an option to show a“virtual view” of the system that graphically depicts the variouscomponents in the system using appropriate icons. As one example, theuser interface 158 may provide a graphical depiction of one or moreprimary storage devices 104, the secondary storage devices 108, dataagents 142 and/or media agents 144, and their relationship to oneanother in the information management system 100. The operationsmanagement functionality can facilitate planning and decision-making.For example, in some embodiments, a user may view the status of some orall jobs as well as the status of each component of the informationmanagement system 100. Users may then plan and make decisions based onthis data. For instance, a user may view high-level informationregarding storage operations for the information management system 100,such as job status, component status, resource status (e.g.,communication pathways, etc.), and other information. The user may alsodrill down or use other means to obtain more detailed informationregarding a particular component, job, or the like. Further examples ofsome reporting techniques and associated interfaces providing anintegrated view of an information management system are provided in U.S.Pat. No. 7,343,453, which is incorporated by reference herein.

The information management system 100 can also be configured to performsystem-wide e-discovery operations in some embodiments. In general,e-discovery operations provide a unified collection and searchcapability for data in the system, such as data stored in the secondarystorage devices 108 (e.g., backups, archives, or other secondary copies116). For example, the information management system 100 may constructand maintain a virtual repository for data stored in the informationmanagement system 100 that is integrated across source applications 110,different storage device types, etc. According to some embodiments,e-discovery utilizes other techniques described herein, such as dataclassification and/or content indexing.

Information Management Policies

As indicated previously, an information management policy 148 caninclude a data structure or other information source that specifies aset of parameters (e.g., criteria and rules) associated with secondarycopy and/or other information management operations.

One type of information management policy 148 is a storage policy.According to certain embodiments, a storage policy generally comprises adata structure or other information source that defines (or includesinformation sufficient to determine) a set of preferences or othercriteria for performing information management operations. Storagepolicies can include one or more of the following items: (1) what datawill be associated with the storage policy; (2) a destination to whichthe data will be stored; (3) datapath information specifying how thedata will be communicated to the destination; (4) the type of storageoperation to be performed; and (5) retention information specifying howlong the data will be retained at the destination (see, e.g., FIG. 1E).

As an illustrative example, data associated with a storage policy can belogically organized into groups. In some cases, these logical groupingscan be referred to as “sub-clients”. A sub-client may represent staticor dynamic associations of portions of a data volume. Sub-clients mayrepresent mutually exclusive portions. Thus, in certain embodiments, aportion of data may be given a label and the association is stored as astatic entity in an index, database or other storage location.Sub-clients may also be used as an effective administrative scheme oforganizing data according to data type, department within theenterprise, storage preferences, or the like. Depending on theconfiguration, sub-clients can correspond to files, folders, virtualmachines, databases, etc. In one exemplary scenario, an administratormay find it preferable to separate e-mail data from financial data usingtwo different sub-clients.

A storage policy can define where data is stored by specifying a targetor destination storage device (or group of storage devices). Forinstance, where the secondary storage device 108 includes a group ofdisk libraries, the storage policy may specify a particular disk libraryfor storing the sub-clients associated with the policy. As anotherexample, where the secondary storage devices 108 include one or moretape libraries, the storage policy may specify a particular tape libraryfor storing the sub-clients associated with the storage policy, and mayalso specify a drive pool and a tape pool defining a group of tapedrives and a group of tapes, respectively, for use in storing thesub-client data. While information in the storage policy can bestatically assigned in some cases, some or all of the information in thestorage policy can also be dynamically determined based on criteria,which can be set forth in the storage policy. For instance, based onsuch criteria, a particular destination storage device(s) (or otherparameter of the storage policy) may be determined based oncharacteristics associated with the data involved in a particularstorage operation, device availability (e.g., availability of asecondary storage device 108 or a media agent 144), network status andconditions (e.g., identified bottlenecks), user credentials, and thelike).

Datapath information can also be included in the storage policy. Forinstance, the storage policy may specify network pathways and componentsto utilize when moving the data to the destination storage device(s). Insome embodiments, the storage policy specifies one or more media agents144 for conveying data associated with the storage policy between thesource (e.g., one or more host client computing devices 102) anddestination (e.g., a particular target secondary storage device 108).

A storage policy can also specify the type(s) of operations associatedwith the storage policy, such as a backup, archive, snapshot, auxiliarycopy, or the like. Retention information can specify how long the datawill be kept, depending on organizational needs (e.g., a number of days,months, years, etc.)

Another type of information management policy 148 is a schedulingpolicy, which specifies when and how often to perform operations.Scheduling parameters may specify with what frequency (e.g., hourly,weekly, daily, event-based, etc.) or under what triggering conditionssecondary copy or other information management operations will takeplace. Scheduling policies in some cases are associated with particularcomponents, such as particular logical groupings of data associated witha storage policy (e.g., a sub-client), client computing device 102, andthe like. In one configuration, a separate scheduling policy ismaintained for particular logical groupings of data on a clientcomputing device 102. The scheduling policy specifies that those logicalgroupings are to be moved to secondary storage devices 108 every houraccording to storage policies associated with the respectivesub-clients.

When adding a new client computing device 102, administrators canmanually configure information management policies 148 and/or othersettings, e.g., via the user interface 158. However, this can be aninvolved process resulting in delays, and it may be desirable to begindata protection operations quickly, without awaiting human intervention.Thus, in some embodiments, the information management system 100automatically applies a default configuration to client computing device102. As one example, when one or more data agent(s) 142 are installed onone or more client computing devices 102, the installation script mayregister the client computing device 102 with the storage manager 140,which in turn applies the default configuration to the new clientcomputing device 102. In this manner, data protection operations canbegin substantially immediately. The default configuration can include adefault storage policy, for example, and can specify any appropriateinformation sufficient to begin data protection operations. This caninclude a type of data protection operation, scheduling information, atarget secondary storage device 108, data path information (e.g., aparticular media agent 144), and the like.

Other types of information management policies 148 are possible,including one or more audit (or security) policies. An audit policy is aset of preferences, rules and/or criteria that protect sensitive data inthe information management system 100. For example, an audit policy maydefine “sensitive objects” as files or objects that contain particularkeywords (e.g., “confidential,” or “privileged”) and/or are associatedwith particular keywords (e.g., in metadata) or particular flags (e.g.,in metadata identifying a document or email as personal, confidential,etc.). An audit policy may further specify rules for handling sensitiveobjects. As an example, an audit policy may require that a reviewerapprove the transfer of any sensitive objects to a cloud storage site,and that if approval is denied for a particular sensitive object, thesensitive object should be transferred to a local primary storage device104 instead. To facilitate this approval, the audit policy may furtherspecify how a secondary storage computing device 106 or other systemcomponent should notify a reviewer that a sensitive object is slated fortransfer.

Another type of information management policy 148 is a provisioningpolicy. A provisioning policy can include a set of preferences,priorities, rules, and/or criteria that specify how client computingdevices 102 (or groups thereof) may utilize system resources, such asavailable storage on cloud storage and/or network bandwidth. Aprovisioning policy specifies, for example, data quotas for particularclient computing devices 102 (e.g., a number of gigabytes that can bestored monthly, quarterly or annually). The storage manager 140 or othercomponents may enforce the provisioning policy. For instance, the mediaagents 144 may enforce the policy when transferring data to secondarystorage devices 108. If a client computing device 102 exceeds a quota, abudget for the client computing device 102 (or associated department) isadjusted accordingly or an alert may trigger.

While the above types of information management policies 148 have beendescribed as separate policies, one or more of these can be generallycombined into a single information management policy 148. For instance,a storage policy may also include or otherwise be associated with one ormore scheduling, audit, or provisioning policies or operationalparameters thereof. Moreover, while storage policies are typicallyassociated with moving and storing data, other policies may beassociated with other types of information management operations. Thefollowing is a non-exhaustive list of items the information managementpolicies 148 may specify:

-   -   schedules or other timing information, e.g., specifying when        and/or how often to perform information management operations;    -   the type of copy 116 (e.g., type of secondary copy) and/or copy        format (e.g., snapshot, backup, archive, HSM, etc.);    -   a location or a class or quality of storage for storing        secondary copies 116 (e.g., one or more particular secondary        storage devices 108);    -   preferences regarding whether and how to encrypt, compress,        deduplicate, or otherwise modify or transform secondary copies        116;    -   which system components and/or network pathways (e.g., preferred        media agents 144) should be used to perform secondary storage        operations;    -   resource allocation among different computing devices or other        system components used in performing information management        operations (e.g., bandwidth allocation, available storage        capacity, etc.);    -   whether and how to synchronize or otherwise distribute files or        other data objects across multiple computing devices or hosted        services; and    -   retention information specifying the length of time primary data        112 and/or secondary copies 116 should be retained, e.g., in a        particular class or tier of storage devices, or within the        information management system 100.

Policies can additionally specify or depend on a variety of historicalor current criteria that may be used to determine which rules to applyto a particular data object, system component, or information managementoperation, such as:

-   -   frequency with which primary data 112 or a secondary copy 116 of        a data object or metadata has been or is predicted to be used,        accessed, or modified;    -   time-related factors (e.g., aging information such as time since        the creation or modification of a data object);    -   deduplication information (e.g., hashes, data blocks,        deduplication block size, deduplication efficiency or other        metrics);    -   an estimated or historic usage or cost associated with different        components (e.g., with secondary storage devices 108);    -   the identity of users, applications 110, client computing        devices 102 and/or other computing devices that created,        accessed, modified, or otherwise utilized primary data 112 or        secondary copies 116;    -   a relative sensitivity (e.g., confidentiality, importance) of a        data object, e.g., as determined by its content and/or metadata;    -   the current or historical storage capacity of various storage        devices;    -   the current or historical network capacity of network pathways        connecting various components within the storage operation cell;    -   access control lists or other security information; and    -   the content of a particular data object (e.g., its textual        content) or of metadata associated with the data object.        Exemplary Storage Policy and Secondary Storage Operations

FIG. 1E includes a data flow diagram depicting performance of storageoperations by an embodiment of an information management system 100,according to an exemplary storage policy 148A. The informationmanagement system 100 includes a storage manger 140, a client computingdevice 102 having a file system data agent 142A and an email data agent142B operating thereon, a primary storage device 104, two media agents144A, 144B, and two secondary storage devices 108A, 108B: a disk library108A and a tape library 108B. As shown, the primary storage device 104includes primary data 112A, which is associated with a logical groupingof data associated with a file system, and primary data 112B, which isassociated with a logical grouping of data associated with email.Although for simplicity the logical grouping of data associated with thefile system is referred to as a file system sub-client, and the logicalgrouping of data associated with the email is referred to as an emailsub-client, the techniques described with respect to FIG. 1E can beutilized in conjunction with data that is organized in a variety ofother manners.

As indicated by the dashed box, the second media agent 144B and the tapelibrary 108B are “off-site”, and may therefore be remotely located fromthe other components in the information management system 100 (e.g., ina different city, office building, etc.). Indeed, “off-site” may referto a magnetic tape located in storage, which must be manually retrievedand loaded into a tape drive to be read. In this manner, informationstored on the tape library 1086 may provide protection in the event of adisaster or other failure.

The file system sub-client and its associated primary data 112A incertain embodiments generally comprise information generated by the filesystem and/or operating system of the client computing device 102, andcan include, for example, file system data (e.g., regular files, filetables, mount points, etc.), operating system data (e.g., registries,event logs, etc.), and the like. The e-mail sub-client, on the otherhand, and its associated primary data 1126, include data generated by ane-mail application operating on the client computing device 102, and caninclude mailbox information, folder information, emails, attachments,associated database information, and the like. As described above, thesub-clients can be logical containers, and the data included in thecorresponding primary data 112A, 1126 may or may not be storedcontiguously.

The exemplary storage policy 148A includes backup copy preferences (orrule set) 160, disaster recovery copy preferences rule set 162, andcompliance copy preferences or rule set 164. The backup copy rule set160 specifies that it is associated with a file system sub-client 166and an email sub-client 168. Each of these sub-clients 166, 168 areassociated with the particular client computing device 102. The backupcopy rule set 160 further specifies that the backup operation will bewritten to the disk library 108A, and designates a particular mediaagent 144A to convey the data to the disk library 108A. Finally, thebackup copy rule set 160 specifies that backup copies created accordingto the rule set 160 are scheduled to be generated on an hourly basis andto be retained for 30 days. In some other embodiments, schedulinginformation is not included in the storage policy 148A, and is insteadspecified by a separate scheduling policy.

The disaster recovery copy rule set 162 is associated with the same twosub-clients 166, 168. However, the disaster recovery copy rule set 162is associated with the tape library 108B, unlike the backup copy ruleset 160. Moreover, the disaster recovery copy rule set 162 specifiesthat a different media agent, namely 144B, will be used to convey thedata to the tape library 108B. As indicated, disaster recovery copiescreated according to the rule set 162 will be retained for 60 days, andwill be generated on a daily basis. Disaster recovery copies generatedaccording to the disaster recovery copy rule set 162 can provideprotection in the event of a disaster or other catastrophic data lossthat would affect the backup copy 116A maintained on the disk library108A.

The compliance copy rule set 164 is only associated with the emailsub-client 168, and not the file system sub-client 166. Compliancecopies generated according to the compliance copy rule set 164 willtherefore not include primary data 112A from the file system sub-client166. For instance, the organization may be under an obligation to storeand maintain copies of email data for a particular period of time (e.g.,10 years) to comply with state or federal regulations, while similarregulations do not apply to the file system data. The compliance copyrule set 164 is associated with the same tape library 108B and mediaagent 144B as the disaster recovery copy rule set 162, although adifferent storage device or media agent could be used in otherembodiments. Finally, the compliance copy rule set 164 specifies thatcopies generated under the compliance copy rule set 164 will be retainedfor 10 years, and will be generated on a quarterly basis.

At step 1, the storage manager 140 initiates a backup operationaccording to the backup copy rule set 160. For instance, a schedulingservice running on the storage manager 140 accesses schedulinginformation from the backup copy rule set 160 or a separate schedulingpolicy associated with the client computing device 102, and initiates abackup copy operation on an hourly basis. Thus, at the scheduled timeslot the storage manager 140 sends instructions to the client computingdevice 102 (i.e., to both data agent 142A and data agent 142B) to beginthe backup operation.

At step 2, the file system data agent 142A and the email data agent 142Boperating on the client computing device 102 respond to the instructionsreceived from the storage manager 140 by accessing and processing theprimary data 112A, 112B involved in the copy operation, which can befound in primary storage device 104. Because the operation is a backupcopy operation, the data agent(s) 142A, 142B may format the data into abackup format or otherwise process the data.

At step 3, the client computing device 102 communicates the retrieved,processed data to the first media agent 144A, as directed by the storagemanager 140, according to the backup copy rule set 160. In some otherembodiments, the information management system 100 may implement aload-balancing, availability-based, or other appropriate algorithm toselect from the available set of media agents 144A, 144B. Regardless ofthe manner the media agent 144A is selected, the storage manager 140 mayfurther keep a record in the storage manager database 146 of theassociation between the selected media agent 144A and the clientcomputing device 102 and/or between the selected media agent 144A andthe backup copy 116A.

The target media agent 144A receives the data from the client computingdevice 102, and at step 4 conveys the data to the disk library 108A tocreate the backup copy 116A, again at the direction of the storagemanager 140 and according to the backup copy rule set 160. The secondarystorage device 108A can be selected in other ways. For instance, themedia agent 144A may have a dedicated association with a particularsecondary storage device(s), or the storage manager 140 or media agent144A may select from a plurality of secondary storage devices, e.g.,according to availability, using one of the techniques described in U.S.Pat. No. 7,246,207, which is incorporated by reference herein.

The media agent 144A can also update its index 153 to include dataand/or metadata related to the backup copy 116A, such as informationindicating where the backup copy 116A resides on the disk library 108A,data and metadata for cache retrieval, etc. The storage manager 140 maysimilarly update its index 150 to include information relating to thestorage operation, such as information relating to the type of storageoperation, a physical location associated with one or more copiescreated by the storage operation, the time the storage operation wasperformed, status information relating to the storage operation, thecomponents involved in the storage operation, and the like. In somecases, the storage manager 140 may update its index 150 to include someor all of the information stored in the index 153 of the media agent144A. After the 30 day retention period expires, the storage manager 140instructs the media agent 144A to delete the backup copy 116A from thedisk library 108A. Indexes 150 and/or 153 are updated accordingly.

At step 5, the storage manager 140 initiates the creation of a disasterrecovery copy 1166 according to the disaster recovery copy rule set 162.

At step 6, illustratively based on the instructions received from thestorage manager 140 at step 5, the specified media agent 144B retrievesthe most recent backup copy 116A from the disk library 108A.

At step 7, again at the direction of the storage manager 140 and asspecified in the disaster recovery copy rule set 162, the media agent144B uses the retrieved data to create a disaster recovery copy 116B onthe tape library 108B. In some cases, the disaster recovery copy 1166 isa direct, mirror copy of the backup copy 116A, and remains in the backupformat. In other embodiments, the disaster recovery copy 1166 may begenerated in some other manner, such as by using the primary data 112A,112B from the primary storage device 104 as source data. The disasterrecovery copy operation is initiated once a day and the disasterrecovery copies 1166 are deleted after 60 days; indexes are updatedaccordingly when/after each information management operation isexecuted/completed.

At step 8, the storage manager 140 initiates the creation of acompliance copy 116C, according to the compliance copy rule set 164. Forinstance, the storage manager 140 instructs the media agent 144B tocreate the compliance copy 116C on the tape library 108B at step 9, asspecified in the compliance copy rule set 164. In the example, thecompliance copy 116C is generated using the disaster recovery copy 1166.In other embodiments, the compliance copy 116C is instead generatedusing either the primary data 112B corresponding to the email sub-clientor using the backup copy 116A from the disk library 108A as source data.As specified, in the illustrated example, compliance copies 116C arecreated quarterly, and are deleted after ten years, and indexes are keptup-to-date accordingly.

While not shown in FIG. 1E, at some later point in time, a restoreoperation can be initiated involving one or more of the secondary copies116A, 116B, 116C. As one example, a user may manually initiate a restoreof the backup copy 116A by interacting with the user interface 158 ofthe storage manager 140. The storage manager 140 then accesses data inits index 150 (and/or the respective storage policy 148A) associatedwith the selected backup copy 116A to identify the appropriate mediaagent 144A and/or secondary storage device 108A.

In other cases, a media agent may be selected for use in the restoreoperation based on a load balancing algorithm, an availability basedalgorithm, or other criteria. The selected media agent 144A retrievesthe data from the disk library 108A. For instance, the media agent 144Amay access its index 153 to identify a location of the backup copy 116Aon the disk library 108A, or may access location information residing onthe disk 108A itself.

When the backup copy 116A was recently created or accessed, the mediaagent 144A accesses a cached version of the backup copy 116A residing inthe index 153, without having to access the disk library 108A for someor all of the data. Once it has retrieved the backup copy 116A, themedia agent 144A communicates the data to the source client computingdevice 102. Upon receipt, the file system data agent 142A and the emaildata agent 142B may unpackage (e.g., restore from a backup format to thenative application format) the data in the backup copy 116A and restorethe unpackaged data to the primary storage device 104.

Exemplary Applications of Storage Policies

The storage manager 140 may permit a user to specify aspects of thestorage policy 148A. For example, the storage policy can be modified toinclude information governance policies to define how data should bemanaged in order to comply with a certain regulation or businessobjective. The various policies may be stored, for example, in themanagement database 146. An information governance policy may comprise aclassification policy, which is described herein. An informationgovernance policy may align with one or more compliance tasks that areimposed by regulations or business requirements. Examples of informationgovernance policies might include a Sarbanes-Oxley policy, a HIPAApolicy, an electronic discovery (E-Discovery) policy, and so on.

Information governance policies allow administrators to obtain differentperspectives on all of an organization's online and offline data,without the need for a dedicated data silo created solely for eachdifferent viewpoint. As described previously, the data storage systemsherein build a centralized index that reflects the contents of adistributed data set that spans numerous clients and storage devices,including both primary and secondary copies, and online and offlinecopies. An organization may apply multiple information governancepolicies in a top-down manner over that unified data set and indexingschema in order to permit an organization to view and manipulate thesingle data set through different lenses, each of which is adapted to aparticular compliance or business goal. Thus, for example, by applyingan E-discovery policy and a Sarbanes-Oxley policy, two different groupsof users in an organization can conduct two very different analyses ofthe same underlying physical set of data copies, which may bedistributed throughout the organization and information managementsystem.

A classification policy defines a taxonomy of classification terms ortags relevant to a compliance task and/or business objective. Aclassification policy may also associate a defined tag with aclassification rule. A classification rule defines a particularcombination of criteria, such as users who have created, accessed ormodified a document or data object; file or application types; contentor metadata keywords; clients or storage locations; dates of datacreation and/or access; review status or other status within a workflow(e.g., reviewed or un-reviewed); modification times or types ofmodifications; and/or any other data attributes in any combination,without limitation. A classification rule may also be defined usingother classification tags in the taxonomy. The various criteria used todefine a classification rule may be combined in any suitable fashion,for example, via Boolean operators, to define a complex classificationrule. As an example, an E-discovery classification policy might define aclassification tag “privileged” that is associated with documents ordata objects that (1) were created or modified by legal departmentstaff, or (2) were sent to or received from outside counsel via email,or (3) contain one of the following keywords: “privileged” or “attorney”or “counsel”, or other like terms.

One specific type of classification tag, which may be added to an indexat the time of indexing, is an entity tag. An entity tag may be, forexample, any content that matches a defined data mask format. Examplesof entity tags might include, e.g., social security numbers (e.g., anynumerical content matching the formatting mask XXX-XX-XXXX), credit cardnumbers (e.g., content having a 13-16 digit string of numbers), SKUnumbers, product numbers, etc.

A user may define a classification policy by indicating criteria,parameters or descriptors of the policy via a graphical user interface,such as a form or page with fields to be filled in, pull-down menus orentries allowing one or more of several options to be selected, buttons,sliders, hypertext links or other known user interface tools forreceiving user input, etc. For example, a user may define certain entitytags, such as a particular product number or project ID code that isrelevant in the organization. In some implementations, theclassification policy can be implemented using cloud-based techniques.For example, the storage devices may be cloud storage devices, and thestorage manager 140 may execute cloud service provider API over anetwork to classify data stored on cloud storage devices.

Exemplary Secondary Copy Formatting

The formatting and structure of secondary copies 116 can vary, dependingon the embodiment. In some cases, secondary copies 116 are formatted asa series of logical data units or “chunks” (e.g., 512 MB, 1 GB, 2 GB, 4GB, or 8 GB chunks). This can facilitate efficient communication andwriting to secondary storage devices 108, e.g., according to resourceavailability. For example, a single secondary copy 116 may be written ona chunk-by-chunk basis to a single secondary storage device 108 oracross multiple secondary storage devices 108. In some cases, users canselect different chunk sizes, e.g., to improve throughput to tapestorage devices.

Generally, each chunk can include a header and a payload. The payloadcan include files (or other data units) or subsets thereof included inthe chunk, whereas the chunk header generally includes metadata relatingto the chunk, some or all of which may be derived from the payload. Forexample, during a secondary copy operation, the media agent 144, storagemanager 140, or other component may divide the associated files intochunks and generate headers for each chunk by processing the constituentfiles. The headers can include a variety of information such as fileidentifier(s), volume(s), offset(s), or other information associatedwith the payload data items, a chunk sequence number, etc. Importantly,in addition to being stored with the secondary copy 116 on the secondarystorage device 108, the chunk headers can also be stored to the index153 of the associated media agent(s) 144 and/or the index 150. This isuseful in some cases for providing faster processing of secondary copies116 during restores or other operations. In some cases, once a chunk issuccessfully transferred to a secondary storage device 108, thesecondary storage device 108 returns an indication of receipt, e.g., tothe media agent 144 and/or storage manager 140, which may update theirrespective indexes 153, 150 accordingly. During restore, chunks may beprocessed (e.g., by the media agent 144) according to the information inthe chunk header to reassemble the files.

Data can also be communicated within the information management system100 in data channels that connect the client computing devices 102 tothe secondary storage devices 108. These data channels can be referredto as “data streams”, and multiple data streams can be employed toparallelize an information management operation, improving data transferrate, among providing other advantages. Example data formattingtechniques including techniques involving data streaming, chunking, andthe use of other data structures in creating copies (e.g., secondarycopies) are described in U.S. Pat. Nos. 7,315,923 and 8,156,086, and8,578,120, each of which is incorporated by reference herein.

FIGS. 1F and 1G are diagrams of example data streams 170 and 171,respectively, which may be employed for performing data storageoperations. Referring to FIG. 1F, the data agent 142 forms the datastream 170 from the data associated with a client computing device 102(e.g., primary data 112). The data stream 170 is composed of multiplepairs of stream header 172 and stream data (or stream payload) 174. Thedata streams 170 and 171 shown in the illustrated example are for asingle-instanced storage operation, and a stream payload 174 thereforemay include both single-instance (“SI”) data and/or non-SI data. Astream header 172 includes metadata about the stream payload 174. Thismetadata may include, for example, a length of the stream payload 174,an indication of whether the stream payload 174 is encrypted, anindication of whether the stream payload 174 is compressed, an archivefile identifier (ID), an indication of whether the stream payload 174 issingle instanceable, and an indication of whether the stream payload 174is a start of a block of data.

Referring to FIG. 1G, the data stream 171 has the stream header 172 andstream payload 174 aligned into multiple data blocks. In this example,the data blocks are of size 64 KB. The first two stream header 172 andstream payload 174 pairs comprise a first data block of size 64 KB. Thefirst stream header 172 indicates that the length of the succeedingstream payload 174 is 63 KB and that it is the start of a data block.The next stream header 172 indicates that the succeeding stream payload174 has a length of 1 KB and that it is not the start of a new datablock. Immediately following stream payload 174 is a pair comprising anidentifier header 176 and identifier data 178. The identifier header 176includes an indication that the succeeding identifier data 178 includesthe identifier for the immediately previous data block. The identifierdata 178 includes the identifier that the data agent 142 generated forthe data block. The data stream 171 also includes other stream header172 and stream payload 174 pairs, which may be for SI data and/or fornon-SI data.

FIG. 1H is a diagram illustrating the data structures 180 that may beused to store blocks of SI data and non-SI data on the storage device(e.g., secondary storage device 108). According to certain embodiments,the data structures 180 do not form part of a native file system of thestorage device. The data structures 180 include one or more volumefolders 182, one or more chunk folders 184/185 within the volume folder182, and multiple files within the chunk folder 184. Each chunk folder184/185 includes a metadata file 186/187, a metadata index file 188/189,one or more container files 190/191/193, and a container index file192/194. The metadata file 186/187 stores non-SI data blocks as well aslinks to SI data blocks stored in container files. The metadata indexfile 188/189 stores an index to the data in the metadata file 186/187.The container files 190/191/193 store SI data blocks. The containerindex file 192/194 stores an index to the container files 190/191/193.Among other things, the container index file 192/194 stores anindication of whether a corresponding block in a container file190/191/193 is referred to by a link in a metadata file 186/187. Forexample, data block B2 in the container file 190 is referred to by alink in the metadata file 187 in the chunk folder 185. Accordingly, thecorresponding index entry in the container index file 192 indicates thatthe data block B2 in the container file 190 is referred to. As anotherexample, data block B1 in the container file 191 is referred to by alink in the metadata file 187, and so the corresponding index entry inthe container index file 192 indicates that this data block is referredto.

As an example, the data structures 180 illustrated in FIG. 1H may havebeen created as a result of two storage operations involving two clientcomputing devices 102. For example, a first storage operation on a firstclient computing device 102 could result in the creation of the firstchunk folder 184, and a second storage operation on a second clientcomputing device 102 could result in the creation of the second chunkfolder 185. The container files 190/191 in the first chunk folder 184would contain the blocks of SI data of the first client computing device102. If the two client computing devices 102 have substantially similardata, the second storage operation on the data of the second clientcomputing device 102 would result in the media agent 144 storingprimarily links to the data blocks of the first client computing device102 that are already stored in the container files 190/191. Accordingly,while a first storage operation may result in storing nearly all of thedata subject to the storage operation, subsequent storage operationsinvolving similar data may result in substantial data storage spacesavings, because links to already stored data blocks can be storedinstead of additional instances of data blocks.

If the operating system of the secondary storage computing device 106 onwhich the media agent 144 operates supports sparse files, then when themedia agent 144 creates container files 190/191/193, it can create themas sparse files. A sparse file is type of file that may include emptyspace (e.g., a sparse file may have real data within it, such as at thebeginning of the file and/or at the end of the file, but may also haveempty space in it that is not storing actual data, such as a contiguousrange of bytes all having a value of zero). Having the container files190/191/193 be sparse files allows the media agent 144 to free up spacein the container files 190/191/193 when blocks of data in the containerfiles 190/191/193 no longer need to be stored on the storage devices. Insome examples, the media agent 144 creates a new container file190/191/193 when a container file 190/191/193 either includes 100 blocksof data or when the size of the container file 190 exceeds 50 MB. Inother examples, the media agent 144 creates a new container file190/191/193 when a container file 190/191/193 satisfies other criteria(e.g., it contains from approximately 100 to approximately 1000 blocksor when its size exceeds approximately 50 MB to 1 GB).

In some cases, a file on which a storage operation is performed maycomprise a large number of data blocks. For example, a 100 MB file maycomprise 400 data blocks of size 256 KB. If such a file is to be stored,its data blocks may span more than one container file, or even more thanone chunk folder. As another example, a database file of 20 GB maycomprise over 40,000 data blocks of size 512 KB. If such a database fileis to be stored, its data blocks will likely span multiple containerfiles, multiple chunk folders, and potentially multiple volume folders.Restoring such files may require accessing multiple container files,chunk folders, and/or volume folders to obtain the requisite datablocks.

Improving the Assignment of Data Agent Proxies for ExecutingVirtual-Machine Secondary Copy Operations Including Streaming BackupJobs

FIG. 2A is a block diagram illustrating some salient portions of asystem 200 for improving the assignment of data agent proxies in VMsecondary copy operations including streaming backup jobs according toan illustrative embodiment of the present invention. System 200 is astorage management system, which may be an embodiment of an informationmanagement system, and which illustratively comprises: secondary storagesubsystem 118, comprising secondary storage computing devices 106executing respective media agents 144, and secondary storage devices 108(e.g., disk, tape, etc.); virtual machine cluster 202; primary storagedevice 204-1; storage manager 240; and host computing device 252,hosting virtual server data agent 242-2. An illustrative data flow for avirtual-machine secondary copy operation is collectively depicted by thebold dotted arrows 221, 222, and 223. The components may be logicallyinterconnected as shown by the solid arrows. The physical communicationsinfrastructure required to support these logical connections is wellknown in the art and may be any suitable electronic communicationsinfrastructure, such as that described in regard to communicationpathways 114 above.

Secondary storage subsystem 118 is described in more detail elsewhereherein. According to the illustrative embodiment, secondary subsystem118 in system 200 may comprise secondary storage computing devices 106,each of which executes at least one respective media agent 144, and alsomay comprise secondary storage devices 108 (e.g., disk, tape, etc.).According to the illustrative embodiment, the secondary storage devices108 are all accessible by every one of the secondary storage computingdevice 106, though the invention is not so limited. Secondary storagedevices 108 store secondary copies 116 (not shown in the present figure)of the VM data stores being backed up.

Virtual machine cluster 202 comprises a number of VMs and is describedin more detail in a subsequent figure.

Primary storage device 204-1 is a data storage device analogous tostorage device 104 described in an earlier figure, e.g., a disk, astorage array, etc., and additionally comprises the data store(s) (e.g.,primary data 112) of one or more VMs operating in VM cluster 202. As aresult, primary storage device 204-1 is a data source for secondary copyoperations in system 200, such as streaming backup jobs for one or moreVMs whose data stores are stored in storage device 204-1.

The bold dotted unidirectional arrows 221, 222, and 223, collectivelydepict a logical data flow for a secondary copy operation originatingwith a VM data store (e.g., 112 not shown in the present figure) onprimary storage device 204-1 and terminating to a secondary storagedevice 108 (e.g., tape media) which stores secondary copies of thesource (e.g., secondary copies 116 not shown in the present figure).Secondary copy operations are discussed in more detail elsewhere herein.Illustratively, data flow segment 221 originates at the primary storagedevice 204-1 and terminates at the data agent handling this part of thesecondary copy operation (e.g., at VSDA 242-2); data flow segment 222originates at the data agent (e.g., VSDA 242-2) and terminates at themedia agent 144 which is handling this part of the secondary copyoperation; data flow segment 223 originates at the media agent 144 andterminates at the secondary storage device 108 (e.g., tape) that storesthe resulting secondary copy (e.g., a full backup copy, an incrementalbackup copy, etc.).

Data flow segment 221 may comprise more than one data stream. Forexample, data flow segment 221 may occur in the form of three concurrentdata streams that transport data from the source data store to VSDA242-2 using network resources. As explained elsewhere, using more thanone data stream makes it possible to increase the effective bandwidth ofthe secondary copy operation and thus enables faster backups. The numberof data streams that may be in use concurrently at a proxy such as host252 may be an important consideration in how a particular secondary copyoperation occurs within a given backup job, as explained in furtherdetail in another figure.

Storage manager 240 is analogous to storage manager 140 described inmore detail elsewhere herein, and further comprises additionalfunctionality for operating in system 200, e.g., designating a certaindata agent as coordinator in a backup job; designating other data agentsas controllers in the backup job; tracking the coordinator/controllerroles of the respective data agents, e.g., virtual server data agents242; tracking data streams relative to virtual machine backup jobs,e.g., the maximum number of data streams allowed for the backup job;tracking network topology/connectivity information, includinginformation about mode of access from a given data agent to a VM datastore; tracking operational properties of proxies in system 200;tracking operational properties of virtual machines in system 200, etc.,without limitation. The information tracked by storage manager 240 maybe stored in a management database, e.g., management database 146 notshown in the present figure, which is part of and/or associated withstorage manager 240.

Virtual server data agent 242 (or “VSDA 242”) (e.g., 242-1, 242-2,242-3) is a data agent, analogous to data agent 142, that is speciallydesigned and configured to operate vis-à-vis one or more virtualmachines. VSDA 242 handles secondary copy operations for virtualmachines, e.g., extracting primary data from the VM's data store,reading and interpreting metadata, formatting the payload and metadataand transmitting to media agent 144, and communicating with storagemanager 240 for instructions and status reporting, etc. VSDA 242 may bereferred to herein as a “virtual server agent,” although it should benoted that the subject virtual machine need not run on a designated“server” computing device. In other words, a virtual server data agentis a data agent that is specialized for taking part in secondary copyoperations relating to virtual machine(s), whether the targeted virtualmachine executes on a dedicated VM server or on another computingdevice, such as a client computing device 102 that also performs otherfunctions besides executing VMs. Depending on the implementation, VSDA242 may be specialized for a particular manufacturer's VM server, or maybe designed to work with a variety of VM servers and/or VM types. Thepresent invention is not limited as to the type of VM that a VSDA 242may protect.

Host computing device 252 (or “host 252”) is a computing device that isanalogous to client computing device 102 described elsewhere herein, andalso comprises additional functionality for operating in system 200,e.g., executing VSDA 242-2, communicating with a primary storage device204-1 that comprises VM data store(s), etc. Host 252 may execute anynumber of data agents, including one or more VSDAs 242. Host 252 isconsidered a proxy for VM secondary copy operations as explained in moredetail elsewhere herein, e.g., executing certain operations in method300.

System 200 is not limited to the number, interconnectivity, types,and/or ratios of components shown in the present figure. For example,system 200 may further comprise other VM clusters 202, any number ofVMs, additional host computing devices 252, any number of primarystorage devices 204, and more or fewer secondary storage devices 108.Likewise, the composition of an element such as VM cluster 202 may varyfrom what is shown herein. Likewise, the interconnectivity amongcomponents shown in the present figure and in other figures herein isillustrative so that a variety of access modes may be discussed indetail, but not all depicted interconnectivity and access modes arerequired for every embodiment of the present invention. For example,Fibre Channel—Storage Area Network (“FC SAN”) access from VSDA 242-2 toprimary storage device 204-1 (see, e.g., FIG. 2B) need not beimplemented in every embodiment of the present invention; conversely, insome embodiments, FC SAN may be the only access mode configured foraccessing virtual machine data stores. More details are given insubsequent figures. Moreover, although the depicted system 200 depictsvirtual machines as the only sources of primary data, other sources ofprimary data may be configured in system 200 and/or in otherembodiments, such as client computing devices 102 executingapplications/file systems 110 and corresponding data agents 142 as shownin other figures herein.

FIG. 2B is a block diagram illustrating some salient details of system200, including a virtual machine cluster 202 and its constituentcomponents. VM cluster 202 is a logical grouping of virtualmachine-related resources, which may comprise: VM server 203-1, whichcomprises primary storage device 204-2 and executes virtual machinesVM-A, VM-B, . . . , and VM-N; VM server 203-2, which executes virtualmachines VM-P, VM-Q, VM-R, . . . , and VM-X; primary storage device204-3; and primary storage device 204-4. The components inside VMcluster 202 may be logically interconnected as shown by the solidarrows. The physical communications infrastructure required to supportthese logical connections is well known in the art and may be anysuitable electronic communications infrastructure, such as thatdescribed in regard to communication pathways 114 above. Primary storagedevice 204-1 is shown outside VM cluster 202, and is logicallyinterconnected to VM-R and host 252 by Fibre Channel Storage AreaNetwork (“FC SAN”) connections 205 and 206, respectively. Components204-1, 240, 242, and 252 are described in more detail in another figure.

VM servers 203 (e.g., 203-1, 203-2) are computing devices that areillustratively dedicated servers that act as a platform for VMs, such asproviding VMs to any user of system 200. For example, a VM server 203may execute a VMware vSphere® suite from VMware, Inc. of Palo Alto,Calif., USA, to provide a virtualization platform for any number ofusers in the corporate network, though the present invention is notlimited to the VMware platform or to any particular type of VM or VMserver. Moreover, VM server 203 need not be dedicated as a VM resource,and may also provide other data processing services. VM server 203 iswell known in the art and may provide any number of VMs within system200.

Primary storage device 204-1, which was described in more detail in apreceding figure, is illustratively connected to VM-R via FC SANcommunication pathway 205, and is likewise connected to host 252 via FCSAN communication pathway 206. These Fibre Channel interconnectionsenable host 252 (e.g., executing VSDA 242-2) to have direct access fromhost 252 to VM-R's data store in primary storage device 204-1.Accordingly, in a secondary copy operation for VM-R handled by VSDA242-2, VSDA 242-2 may access VM-R's data store on storage device 204-1directly via the storage area network comprising pathway 206, withouthaving to communicate to/from VM server 203-2, which hosts VM-R. Thismode of access, via FC SAN, is the preferred mode of access to a VM datastore according to the illustrative embodiment, because it does not tapany processing/communications resources on the VM's host server (e.g.,203-2) and thus causes less impact to the production environment. Tiersof preference for access modes to VM data stores are discussed in moredetail in a later figure (see, e.g., block 608 in FIG. 6).

Primary storage device 204-2, which is illustratively a component of VMserver 203-1, is analogous to primary storage device 104 andadditionally comprises the data store(s) (e.g., primary data 112) of oneor more VMs executing on VM server 203-1, such as VM-A.

Primary storage devices 204-3 and 204-4 are illustrative components ofVM cluster 202 and each is interconnected to both VM server 203-1 and VMserver 203-2. Primary storage devices 204-3 and 204-4 are primarystorage devices analogous to primary storage device 104 and additionallycomprise the respective data store(s) (e.g., primary data 112) of one ormore VMs in cluster 202, such as VM-B, VM-N, VM-P, etc.

FIG. 2C is a block diagram illustrating some salient details of system200, including virtual-server data agent proxies 1-3, a coordinator dataagent 242-1, and controller data agents 242-2 and 242-3. As depicted inthe present figure: VM-N, which is designated virtual-server data agentproxy 1 (or “proxy 1”), executes virtual-server data agent 242-1, whichoperates as a coordinator data agent, comprises priority list 243, andexecutes inter-process communications module 245; host computing device252, which is designated VSDA proxy 2 (or “proxy 2”), executes VSDA242-2, which operates as a controller data agent; and VM-X, which isdesignated VSDA proxy 3 (or “proxy 3”), executes VSDA 242-3, whichoperates as a controller data agent. Coordinator data agent 242-1communicates with controller data agent 242-2 and with controller dataagent 242-3 using logical communication pathways 274 and inter-processcommunications module 245. All VSDAs 242 are also in communication withstorage manager 240 as components of storage management system 200according to techniques well known in the art.

In the context of the present disclosure, a proxy is a platform thatexecutes a data agent, such as a virtual server data agent 242 which maybe involved in performing secondary copy operations for a virtualmachine. The platform may itself be a virtual machine that is capable ofexecuting a data agent for backing up other virtual machines. Proxy 1 issuch a proxy, i.e., virtual machine VM-N, which executes on VM server203-1 and executes coordinator data agent 242-1 for backing up othervirtual machines, such as VM-A, VM-B, VM-P, etc. Likewise, proxy 3 isanother virtual machine, VM-X, which executes on VM server 203-2, andwhich executes controller data agent 242-3 for backing up other virtualmachines, such as VM-A, VM-B, and VM-P, etc. A virtual machine-basedproxy such as VM-N and VM-X may execute any number and/or types of dataagents, not just virtual server data agents 242.

Alternatively, the proxy may be a computing device that directlyexecutes a data agent such as a virtual server data agent 242 which maybe involved in performing secondary copy operations for a virtualmachine. Proxy 2 is such a proxy, i.e., host 252, which executes virtualserver data agent 242-2 for backing up virtual machines such as VM-A,VM-B, VM-Q, VM-R, etc. A proxy such as host 252 may execute any numberand/or types of data agents, not just virtual server data agents 242. Insum, a proxy may represent one of: (a) a first virtual machine thatexecutes on a first computing device, wherein the first virtual machineexecutes a virtual-server data agent for virtual-machine backup, and (b)a second computing device that executes a virtual-server data agent forvirtual-machine backup.

Virtual server data agent (“VSDA”) 242-1 illustratively acts in acoordinator role for a particular backup job, based on receiving thecoordinator designation from storage manager 240, for example when thebackup job begins. Therefore, this data agent may be referred to hereinas the “coordinator data agent” or “coordinator.” As shall be seenlater, the coordinator data agent comprises enhanced functionality thatimproves the way in which proxies are assigned for executing a VM backupjob. More details on this enhanced functionality are given in subsequentfigures. The coordinator data agent may or may not actually participatein a secondary copy operation during the backup job, but the coordinatordata agent comprises the functionality for doing so if need be. In otherwords, the proxy that executes the coordinator data agent may alsoperform one or more secondary copy operations in the backup job.

Virtual server data agents (“VSDA”) 242-2 and 242-3 illustratively actin a controller role for a particular backup job, based on receiving thecontroller designation from storage manager 240 and/or from coordinatordata agent 242-1, for example when the backup job begins, after thecoordinator role has been assigned to another data agent. Therefore,this data agent may be referred to herein as the “controller data agent”or “controller.” As shall be seen later, the controller data agentcomprises enhanced functionality that improves the way in which proxiesare assigned for executing a VM backup job. More details on thisenhanced functionality are given in subsequent figures. The controllerdata agent may or may not actually participate in a secondary copyoperation during the backup job, but the controller data agent comprisesthe functionality for doing so if need be. In other words, a proxy thatexecutes the controller data agent may also perform one or moresecondary copy operations in the backup job.

Priority list 243 is generated, maintained, and used by the proxy thatexecutes the coordinator data agent, illustratively by proxy 1, which isembodied as VM-N executing data agent 242-1. Priority list 243 is a datastructure that comprises a list of virtual machines awaiting backup in agiven backup job and also lists one or more proxies associated with eachVM, which proxy(ies) have been determined to be eligible to back up therespective VM. The ordering of the VMs in the priority list is based ona number of considerations, including the number of eligible proxies andthe storage size of the VM's data store, as described in more detail inregard to FIG. 5. Proxy eligibility is discussed in further detail inregard to FIG. 6. Table 1 below shows an illustrative representation ofa first-round priority list 243 at the beginning of a backup job for VMsA, B, P, Q, and R:

TABLE 1 Illustrative Priority List 243 Eligible Proxies Storage-Size VMWith Highest-Tier Mode Of Access Metric VM-R 2 9 MB VM-B 1 5 MB VM-P 3 4MB VM-Q 3 2 MB VM-A 1 1 MB

Priority list 243 is not limited to the illustrative form of Table 1,and a person having ordinary skill in the art may, after reading thepresent disclosure, devise additional formats and/or organizationalschemes for the information required by coordinator data agent 242-1 toperform the improved techniques of the present invention. For example,priority list 243 may be embodied as several different lists (e.g.,relational tables); may comprise additional information, such asoperational properties of each listed VM and/or proxy; etc., withoutlimitation.

Inter-process communications module 245 is a functional component ofproxy 1, and may be implemented as executable software and/or firmware,which executes on the underlying computing device that hosts proxy 1,e.g., VM server 203-1. When it executes according to the illustrativeembodiment, module 245 is largely responsible for establishing andmaintaining communications between coordinator data agent 242-1 and anynumber of controller data agents in system 200, such as 242-2 and 242-3.Proxy 2 and proxy 3 also may comprise a respective inter-processcommunications module 245 (not shown here). Accordingly, the coordinatordata agent may use the inter-process communications module 245 todesignate other data agents to act as controllers; to distribute jobinformation thereto; to collect proxy and data agent informationtherefrom; to allow/assign data streams thereto; etc., withoutlimitation.

Inter-process communications module 245 is shown herein as a distinctcomponent to ease understanding of the present disclosure; however,alternative embodiments are also possible within the scope of thepresent invention, e.g., wherein module 245 may be a functionalcomponent of the respective virtual server data agent 242.

Logical communication pathways 274 depict inter-process communicationsbetween the illustrative data agents, e.g., between coordinator dataagent 242-1 and controller 242-2, and also between the coordinator dataagent 242-1 and controller 242-3. Logical communication pathways 274 areenabled at least in part by inter-process communications module 245.

FIG. 3 depicts some salient operations of a method 300 according to anillustrative embodiment of the present invention. Method 300 isillustratively directed at executing a streaming backup job for a set ofVMs in system 200. The salient operations of method 300 described hereinare executed by one or more components of system 200, as detailedfurther below. An illustrative backup job for a set of virtual machinesin system 200 may be triggered by a storage policy stored in managementdatabase 146 in a manner well known in the art.

At block 302, storage manager 240 may choose a VSDA 242 to designate asa coordinator data agent for the backup job. Accordingly, storagemanager 240 may designate VSDA 242-1 to act as coordinator data agent,e.g., by communicating the designation to VSDA 242-1. Storage manager240 may further designate other VSDAs to act as controller data agentsunder the coordination of the coordinator data agent 242-1. Accordingly,storage manager 240 may designate VSDA 242-2 and VSDA 242-3 to act ascontroller data agents, e.g., by communicating the respectivedesignations thereto.

At block 304, the initialization process takes place for the designatedcoordinator data agent 242-1. More detail is provided in a subsequentfigure.

At block 306, coordinator data agent 242-1 may generate an orderedpriority list of the set of VMs to be backed up, e.g., priority list243, which is based on eligible proxies and VM storage size. Asexplained in more detail later, the ordered priority list initiallycomprises the entire set of VMs to be backed up in the backup job; insubsequent rounds (i.e., after block 312) a new/revised ordered prioritylist will comprise VMs that were stranded after a backup attempt atblock 308. Several rounds may be necessary to successfully back up theentire set of VMs. More detail is provided in a subsequent figure.

At block 308, coordinator data agent 242-1 attempts to back up the setof VMs using an allowed number of data streams for the backup job, e.g.,two data streams, but the VMs are not necessarily backed up in the orderof the priority list 243. More detail is provided in a subsequentfigure.

At block 310, which is a decision point, coordinator data agent 242-1determines whether any of the VMs in the set of VMs to be backed up haveremained “stranded,” i.e., could not be backed up in the precedingattempt at block 308. If stranded VMs remain, control passes to block312. Otherwise, after the entire set of VMs has been backed up, thebackup job is considered complete and may successfully end. Ending thebackup job may include reporting job metadata and statistics to storagemanager 240; and may also include rescinding the coordinator andcontroller roles of the participating VSDAs 242 until such time as a newjob is begun.

At block 312, which occurs when stranded VMs remain after an attempt,coordinator data agent 242-1 pends the backup job and restarts thebackup job based only on the stranded VMs, passing control back to block306, where a new priority list is to be generated for the stranded VMs.In this new priority list, the set of eligible proxies for each strandedVM may vary from the eligible proxies in an earlier priority list,because lower tiers of preference for access modes to the stranded VMs'data stores may be allowed in subsequent rounds in order to reduce thechances of re-stranding a VM. Several rounds may be necessary tosuccessfully back up the entire set of VMs. More details are provided ina subsequent figure (see, e.g., block 610 in FIG. 6).

FIG. 4 depicts some salient sub-operations of block 304 of method 300.At block 304, the initialization process takes place for the designatedcoordinator data agent 242-1. In general, coordinator data agent 242-1performs the operations of block 304, in conjunction and/or incommunication with other components of system 200 as detailed below.

At block 402, coordinator data agent 242-1 establishes inter-processcommunications (e.g., using inter-process communications module 254)with the coordinator data agents, e.g., 242-2 and 242-3. In someembodiments, coordinator data agent 242-1 may identify and designate thecontrollers, e.g., at block 302. Block 402 also may comprise coordinatordata agent 242-1 identifying the proxies in system 200 that may beinvolved in the present backup job—the proxies illustratively being theplatforms that execute the respective coordinator and controller dataagents, e.g., proxy 1, proxy 2, and proxy 3.

At block 404, coordinator data agent 242-1 may collect job-relatedinformation for the backup job. The job-related information may becollected by querying storage manager 240 and/or management database146. The job-related information may comprise, without limitation: theidentities of the VMs to be backed up in the present backup job; theoperational properties of each VM, e.g., processing capacity, storageunits, storage capacity of storage units; the number and identities ofthe storage devices (e.g., disks) that house the VMs' data stores to bebacked up (e.g., 204-1, 204-2, 204-3, 204-4); and/or the number of datastreams allowed for the backup job.

The number of data streams allowed for the backup job may be a parameterspecified in the storage policy that governs the backup job. The numberof data streams allowed for the backup job may be a function of thenumber of primary storage devices storing the data stores to be backedup, in the sense that too many data streams directed to or tapping aprimary storage device 204 may be detrimental to the performance of thatprimary storage device in the production environment and hence the needto limit how many data streams may tap the device for a secondary copyoperation. Thus, the specifics of system 200's network topology andresources may determine how many data streams may be allowed for certainbackup jobs.

At block 406, coordinator data agent 242-1 collects operationalproperties of the proxies that may be candidates for backing up the setof VMs to be backed up. The proxy properties may be collected byquerying storage manager 240 and/or management database 146 and/or byquerying the proxies themselves. The proxy properties may comprise,without limitation: the CPU count and/or capacity of the proxy; and/orthe amount of random-access memory (RAM) of the proxy. As explained inmore detail below, the proxy properties affect a maximum limit of datastreams that may be assigned to a given proxy at a system-wide level,across a plurality of active jobs that the proxy may be involved in atany given time.

At block 408, coordinator data agent 242-1 may use the proxy propertiesto determine a maximum limit of data streams that may be assigned toeach respective proxy. Each proxy, e.g., proxy 1, proxy 2, proxy 3, isgiven a system-wide maximum limit of assignable data streams it may useconcurrently across a plurality of active jobs that the proxy may beinvolved in at any given time, including the present job. According tothe illustrative embodiment, the proxy's computing power, as measured inCPU and RAM, will affect how many data streams the proxy is allowed toprocess concurrently at any given time. For example, the number of CPUsin a multiprocessor-equipped proxy may affect the limit of assignabledata streams.

Illustratively, the maximum limit of assignable data streams for a givenproxy=MINIMUM of: (a) (10 data streams for each CPU processor in theproxy), and (b) (1 data stream for each 100 MB RAM in the proxy). Forexample, a proxy with 8 CPUs and 200 MB RAM would receive a maximumlimit of allowable data streams of MINIMUM of [(10*8 CPUs), (2*100 MBRAM)]=2 data streams maximum. A proxy having 2 CPUs and 2 GB RAM wouldreceive a maximum limit of assignable data streams of MINIMUM of ((10*2CPUs), (20*100 MB RAM))=20 data streams maximum.

FIG. 5 depicts some salient sub-operations of block 306 of method 300.At block 306, coordinator data agent 242-1 generates an ordered prioritylist of the set of VMs to be backed up, e.g., priority list 243, whichis based on eligible proxies and VM storage size. The ordered prioritylist initially comprises the entire set of VMs to be backed up in thebackup job; in subsequent rounds (i.e., after block 312) a new/revisedordered priority list will comprise only VMs that were stranded after aprior backup attempt at block 308. Several rounds may be necessary tosuccessfully back up the entire set of VMs.

At block 502, coordinator data agent 242-1 may define a set of VMs thatare to be backed up. Initially, the set comprises all the VMs to bebacked up in the present backup job, e.g., according to a governingstorage policy. In a later round that is needed after VMs were strandedwithout backup (i.e., after block 312), the present block will definethe set of stranded VMs that still remain to be backed up in the presentbackup job.

At block 504, coordinator data agent 242-1 may identify the proxy orproxies that are eligible to back up each VM in the set. Eligibility isillustratively based on predefined modes of access that define how aproxy may access the VM's data store. Each distinct mode of access isgiven a tier of preference, which may determine whether the proxy isconsidered to be eligible to back up the proxy in the present round. Theillustrative embodiment contemplates that only the highest-tier proxieswill be eligible to back up a VM in the initial round, but lower-tierproxies may be eligible in subsequent rounds to address stranded VMs.More details are provided in FIG. 6.

At block 506, coordinator data agent 242-1, having identified whichproxies are eligible to back up a given VM according to tiered accessmodes, generates an association between the VM and its eligible proxies.See, e.g., Table 1, which shows the highest-tier proxy/proxiesassociated with each subject VM in an initial round of generating theordered priority list.

At block 508, coordinator data agent 242-1 orders the set of VMs inorder of increasing number of associated eligible proxies. The rationalehere is that VMs having fewer proxy choices should be backed up (or atleast considered for backup) ahead of VMs with more choices, since thelatter would be less likely to be stranded with more choices of eligibleproxies.

At block 510, which is a decision block, coordinator data agent 242-1may break a tie in the ordering of VMs. If block 508 yields no ties,control passes to block 516 where the ordered priority list is deemed tobe complete. However, to break a tie in the ordering of two or more VMsat block 508, control passes to block 512.

At block 512, coordinator data agent 242-1 calculates a storage-sizemetric for each of the tied VMs, illustratively based on (i) the numberof allocated storage units for the VM (e.g., disks), and (ii) therespective amount of storage space on each unit. Illustratively, thestorage-size metric may be the total amount of storage (e.g., in MB)allocated to the VM. See, e.g., Table 1.

At block 514, coordinator data agent 242-1 may break the tie by orderingVMs with the same number of associated eligible proxies in decreasingorder of the respective storage-size metric, e.g., decreasing totalamount of storage. This is illustrated in Table 1. The rationale here isthat larger data stores should be given preference, because theirbackups may take longer and are therefore more likely to becomestranded, whereas backing up a smaller data store may more easily “fitinto” the backup job.

At block 516, the ordered priority list is considered completed andblock 306 may end here.

FIG. 6 depicts some salient sub-operations of block 504 in block 306 ofmethod 300. At block 504, coordinator data agent 242-1 may identify theproxy or proxies that are eligible to back up each VM as it builds upthe ordered priority list. Eligibility is illustratively based onpredefined modes of access that define how a proxy may access the VM'sdata store. Each distinct mode of access is given a tier of preference,which may determine whether the proxy is considered to be eligible toback up the proxy in the present round. The illustrative embodimentcontemplates that only the highest-tier proxies will be eligible to backup a VM in the initial round, but lower-tier proxies may be eligible insubsequent rounds to address stranded VMs.

At block 602, coordinator data agent 242-1 will begin an execution loopto traverse every VM in the set of VMs. The loop illustrativelycomprises blocks 604, 606, 608, and 610.

At block 604, coordinator data agent 242-1 may analyze data inmanagement database 146 to determine which proxies in system 200 arecandidates to back up the present VM. Only platforms with a properlyinstalled and/or active virtual server data agent 242 that is alsosuitable for the given VM may be a candidate. Accordingly, coordinatordata agent 242-1 generates a set of candidate proxies for backing up thepresent VM.

At block 606, coordinator data agent 242-1 may further analyze data inmanagement database 146 and/or other sources of system 200 to determinean access mode that is available to each candidate proxy for accessingthe VM's data store as the backup source. The access mode may also bereferred to as a “read mode” or “transport mode.” The access modedepends on how a proxy may access the storage device that stores theVM's data store, which means that the access mode is highly dependent oncomponent and network configurations in system 200. Some of the networkinformation may be obtained from network components, such as routers, VMservers/hosts, and/or from the proxy itself.

At block 608, coordinator data agent 242-1 may classify each candidateproxy according to predefined access modes to the VM's data store(s) tobe backed up. Tiers of preference are associated with the differentaccess modes. Illustratively, the access modes and tiers are defined asfollows in decreasing order of preference:

-   -   (I) Storage area network (e.g., FC SAN) access directly to the        storage device storing the VM's data store. This access mode        does not require access or connectivity to the VM's host, e.g.,        VM server 203-2, and therefore generally does not interfere with        the VM host's operations. An illustrative example of this access        mode is shown in FIG. 2B, where VSDA proxy 2 (i.e., host 252)        may access the data store of VM-R on primary storage device        204-1 directly via FC protocol using communication pathway 206.        VM-R is hosted by VM server 203-2, but proxy 2 accesses the        storage device 204-1 directly using FC SAN, without accessing VM        server 203-2. This access mode is classified as the highest tier        of preference.    -   (II) Local access to the storage device storing the VM's data        store from the same computing device that also hosts the VM.        This access mode takes advantage of the co-location of the VM        and the proxy on a certain computing device to access a storage        device that is local to the computing device. An illustrative        example of this access mode is shown in FIG. 2B, where VM-N is a        proxy candidate for VM-A and VM-B, all of which VMs are hosted        by the same computing device, i.e., VM server 203-1. If the data        stores of VM-A and VM-B are on a storage device that is local to        VM server 203-1, such as storage devices 204-2, 204-3, and        204-4, VM-N as proxy 1 may locally access those data stores via        the underlying data connectivity offered by the host VM server        203-1. This access mode makes use of an additional resource,        i.e., a VM server, which is otherwise involved in the production        environment and therefore makes this access mode less desirable.        This access mode is classified as a lower tier of preference        than storage area network access above.    -   (III) Networked access to the computing device that hosts the VM        and its data store, e.g., “network block device.” This access        mode occurs when the proxy lacks direct or local access to a        VM's data store and must instead gain access by tapping the VM's        host for access. The data store may be referred to as a “network        block device.” An illustrative example of this access mode is        shown in FIG. 2B, where VM-X as proxy 3 needs to access the data        store of VM-A, which is part of VM server 203-1. Since VM-X is        hosted by VM server 203-2 and VM-A's data store is stored in        storage device 204-2 on VM server 203-1, VM-X's access as a        proxy is limited to a networked connection to VM server 203-1.        This mode makes use of additional resources, i.e., VM servers,        which are otherwise involved in the production environment and        therefore this access mode is less desirable. This access mode        is classified as a lower tier of preference than local access        above.    -   (IV) Complex networking. This access mode contemplates a more        complex networking access scenario and would therefore be even        less desirable than the networked access mode above and is        therefore classified as an even lower tier of preference.        Examples of complex networking may include, without limitation:        low bandwidth connections which are slow; wireless connections        which may be slow, unreliable, or costly; distant components        that may be plagued by unreliable, slow, and/or costly        connectivity; international components that cross country        boundaries and may be subject to legal constraints, higher        costs, etc. Proxy 1 may be an example of complex networking        access to the data store of VM-R on storage device 204-1.

Accordingly, each candidate proxy that is identified relative to thepresent VM is classified at block 608 according to the tiers ofpreference above. Notably, the mode of access and the correspondingclassification depends on the identity of the VM being backed up andwhere it stores its data store and the identity of the candidate proxy.Thus, any given proxy may be differently classified relative to variousVMs for which it is a candidate for backup. For example, relative toVM-R and its data store on 204-1, proxy 2 would receive the highest tierof preference; but relative to VM-A and its data store on 204-2, proxy 2may receive the lowest tier of preference, as there is no local accessand no “easy” networked access at least as depicted in FIG. 2B.

At block 610, coordinator data agent 242-1 may define the highest-tiercandidate proxies for the VM as the proxies that are eligible to back upthe VM in the present round. As shown in Table 1, only the highest-tierproxies initially become associated with a VM on the priority list. IfVMs become stranded after a first traversal of the priority list, asdescribed in regard to blocks 310 and 312 in FIG. 3, when method 300reaches block 610 in the next round of processing, the next lower tierof preference would also be allowed for making candidate proxieseligible in order to broaden the field of possibilities for successfullyfinding the resources to timely back up the VMs. Assuming that all theVMs were stranded after a first round, an example of the new prioritylist generated at block 306 might look like this, using the highest andnext-highest tiers of preference to define eligible proxies:

TABLE 2 Illustrative Priority List 243 for Stranded VMs in a SecondRound VM Eligible Proxies Storage-Size Metric VM-R 2, 3 9 MB VM-B 1, 3 5MB VM-P 3, 1 4 MB VM-Q 3, 1 2 MB VM-A 1, 3 1 MB

After block 610 completes, control passes back to block 602 for the nextVM in the set of VMs. After all VMs in the set have been analyzed andeligible proxies found for them, block 504 may end.

FIG. 7 depicts some salient sub-operations of block 308 of method 300.

At block 308, coordinator data agent 242-1 attempts to back up the setof VMs using an allowed number of data streams for the backup job, e.g.,two data streams, but the VMs are not necessarily backed up in the orderof the priority list 243, as will be seen from the detailed descriptionherein.

At block 702, which may be reached after blocks 716 and/or 720,coordinator data agent 242-1 must first determine whether any datastreams are currently allowed to be started in the present backup job,and if they are all in use and none is currently available, coordinatordata agent 242-1 waits until a data stream is released and becomesavailable, e.g., after a VM backup is completed. The number of alloweddata streams for the backup job was obtained at block 404.

At block 704, having determined that a new data stream is allowed,coordinator data agent 242-1 must determine which proxy is to bedesignated the next available proxy, i.e., which proxy to use for thenext VM backup in the present backup job. Referring to FIGS. 2B and 2Cand Table 1 as an example, coordinator data agent 242-1 must determinewhether proxy 1, 2, or 3 should be the next available proxy. Thisdetermination is based on stream utilization at the proxies and moredetail in this regard is given in a subsequent figure. In general, thepurpose of this block is to choose a less busy proxy as the bestcandidate for the next operation in the backup job. It should be notedthat coordinator data agent 242-1 may itself be the next available proxyand may perform any number of secondary storage operations in the backupjob, while also carrying out its role of coordinator. On the other hand,the next available proxy may be a controller data agent. According tothe illustrative embodiment, method 300 does not consider a data agent'scoordinator or controller role when designating the next availableproxy, although it may do so in alternative embodiments, e.g., favoringa controller over a coordinator, all other factors being equal, etc.

At block 706, having identified a next available proxy, coordinator dataagent 242-1 may begin traversing the current priority list 243 startingwith the highest priority VM at the top of the list (see, e.g., Table 1)to identify a first VM that is awaiting backup, e.g., VM-R.

At block 708, which is a decision point, coordinator data agent 242-1may determine whether the next available proxy identified at block 704is eligible to back up the VM from block 706. If yes, e.g., proxy 2 inTable 1, control passes to block 712, but if it not eligible, thencontrol passes to block 710 for the next VM on the priority list 243.

At block 710, coordinator data agent 242-1 continues traversing prioritylist 243 to the next preferred VM awaiting backup (e.g., VM-B inTable 1) according to block 706 and 708. If coordinator data agent 242-1has traversed the entire priority list 243 and found no VMs awaitingbackup that the next available proxy is eligible to back up, controlpasses back to block 704 to identify another next available proxy.

At block 712, which is a decision point, coordinator data agent 242-1determines whether the data store of the VM that the next availableproxy is eligible to back up has a suitable data store activity score,illustratively whether the data store activity score is over athreshold. If the data store activity score is NOT over the threshold,control passes to block 716. If the data store activity score is overthe threshold, control passes to block 714. The data activity score isillustratively defined as the number of active backup data streamscurrently in use at the storage device housing the VM's data store.Thus, for example, if storage device 204-1 currently participates in abackup operation with one data stream, its score would be determined tobe 1.

The purpose of the present decision block is to favor VMs whose datastores are currently idle in favor of other VMs, which may be higher inthe priority list 243 but which have active data stores whoseperformance may be impacted by starting the present backup operation.Thus, illustratively, the threshold for the present decision point maybe 1. Thus, for example, if VM-R's data store on storage device 204-1 isalready engaged in a backup operation, its score would be 1, and VM-Rmay get passed over for backup based on the present decision block.

At block 714, which is reached when the data store activity score isover the threshold, coordinator data agent 242-1 may pass control backto block 706 to find another VM on the priority list 243 that isawaiting backup, progressing through the priority list in decreasingorder of VM priority. When block 714 is reached again at a later timeand coordinator data agent 242-1 determines that all the VMs at thispoint exceed the data store activity threshold, i.e., all the VMs forwhich the coordinator data agent is evaluating the next available proxyhave busy data stores, the coordinator data agent 242-1 will incrementthe threshold value to a higher baseline figure and return control backto block 706 to re-traverse the priority list.

At block 716, which is reached when the data store activity score is NOTover the threshold, the process reaches a point where a VM backupoperation is appropriate, because the next available proxy identified atblock 704 is eligible to back up the VM identified at block 706 and alsothe VM's data store is not too busy. Accordingly, coordinator data agent242-1 may spawn a VM backup process at the next available proxydetermined at block 704 which will occur at block 718; coordinator dataagent 242-1 will then “ask” for another data stream by passing controlback to block 702.

At block 718, the next available proxy identified at block 704 performsthe secondary copy operations of the backup job for the VM, e.g., astreaming backup of the VM. The operations conducted by the proxy andthe virtual server data agent 242 at this point are well known in theart. For example, VSDA 242 may format the VM's data from the data storeand transmit it to a media agent 144 (see, e.g., logical data flows 221and 222). For example, the media agent 144 will further manipulate(e.g., deduplicate) and index the data for storage to a secondarystorage device 108 (see, e.g., logical data flow 223). This block mayalso include the proxy reporting statistics and index information tostorage manager 240, and also reporting the VM backup being completed tocoordinator data agent 242-1, as well as releasing any data streams usedin performing the VM backup, e.g., by notifying coordinator data agent242-1 to that effect.

At block 720, following the successful completion of the VM's backup,coordinator data agent 242-1 may remove the backed up VM from prioritylist 243. Coordinator data agent 242-1 will then “ask” for another datastream by passing control back to block 702.

FIG. 8 depicts some salient sub-operations of block 704 in block 308 ofmethod 300. At block 704, coordinator data agent 242-1 must determinewhich proxy to designate as the next available proxy, i.e., which proxywill perform the next VM backup in the backup job.

At block 802, coordinator data agent 242-1 may define a set of candidateproxies that are suitable for a currently allowed data stream. Thedetermination may be based on analyzing the current priority list 243,polling storage manager 240, consulting a local data structure generatedin the course of generating priority list 243, etc., and/or anycombination thereof.

At block 804, coordinator data agent 242-1 will begin an execution loopto evaluate all the candidate proxies. The loop illustratively comprisesblocks 806 and 808.

At block 806, coordinator data agent 242-1 may identify the number ofdata streams currently active at the proxy across any and all jobs thatthe proxy is currently participating in. Thus, the number of currentlyactive data streams at the proxy is a global figure that may reachacross several jobs currently operating in system 200. The purpose ofusing this figure is to better balance the candidate proxies in asystem-wide context rather than merely analyzing the present backup job.

At block 808, coordinator data agent 242-1 may compute a streamutilization score for the proxy. The stream utilization score may bebased on: (i) the maximum data-stream limit for the proxy (e.g., fromblock 408), and (ii) the number of currently active data streams at theproxy across all jobs. Illustratively, the stream utilization score forthe proxy is the percentage value of the ratio of element (ii) toelement (i), i.e., utilization=(ii)/(i) %. Control passes back to block804 so that coordinator data agent 242-1 may evaluate the streamutilization of all candidate proxies.

At block 810, having evaluated the current stream utilization at allcandidate proxies, coordinator data agent 242-1 may choose the candidateproxy with the lowest stream utilization score. Accordingly, coordinatordata agent 242-1 may designate the chosen proxy as the “next availableproxy” and may then assign the currently available data stream in thebackup job to the next available proxy for further processing. It shouldbe remembered that the next available proxy identified at block 704becomes the basis for finding a VM on the priority list for which theproxy is eligible to back up, as described in more detail in FIG. 7.

In regard to the components, blocks, operations and/or sub-operationsdescribed in reference to FIGS. 2A-8, other embodiments are possiblewithin the scope of the present invention, such that the above-recitedcomponents, steps, blocks, operations, and/ormessages/requests/queries/instructions/communications are differentlyarranged, sequenced, sub-divided, organized, and/or combined. In someembodiments, a different component may initiate or execute a givenoperation. In some components, the decisions may be based on differentconsiderations and/or scores. Also, in some embodiments, scores may bebased on different parameters, weights, and/or formulas, withoutdeparting from the scope of the present invention.

Example Embodiments

According to an example embodiment of the present invention, acomputer-implemented method for determining a per-proxy limit of datastreams allowed for backup operations in a storage management system,the method comprising: (I) designating, by a storage manager componentof the storage management system, a first data agent to act ascoordinator of a first backup job, wherein the first backup job isconfigured to perform secondary copy operations for a first set ofvirtual machines in the storage management system, wherein thecoordinator data agent executes on a first virtual machine, and whereinthe first virtual machine is designated a first proxy, and wherein thefirst virtual machine executes on a first computing device having one ormore processors and non-transitory computer-readable memory; (II)designating, by the storage manager, a second data agent to act ascontroller in the first backup job, wherein the controller data agentexecutes on a second computing device having one or more processors andnon-transitory computer-readable memory, and wherein the secondcomputing device is designated a second proxy; (III) collecting, by thecoordinator data agent, information about operational properties of thefirst proxy and the second proxy; (IV) determining, by the coordinatordata agent, a respective maximum limit of data streams assignable toeach of the first proxy and the second proxy, wherein the respectivemaximum limit of data streams is based on the operational properties ofeach respective proxy; and (V) wherein each proxy may concurrently useno more than the respective maximum limit of data streams in the courseof performing one or more backup jobs in the storage management system,including while performing the first backup job.

The above-recited method may further comprise: assigning, by thecoordinator data agent, a first data stream to the first proxy in thecourse of performing the first backup job, wherein the first data streamoriginates at a first storage device comprising virtual-machine databeing backed up in the first backup job and terminates at thecoordinator data agent that executes on the first proxy; and wherein thefirst proxy concurrently uses no more than the maximum limit of datastreams determined by the coordinator data agent for the first proxybased on the operational properties of the first proxy. Theabove-recited method may further comprise: assigning, by the coordinatordata agent, a first data stream to the second proxy in the course ofperforming the first backup job, wherein the first data streamoriginates at a first storage device comprising virtual-machine databeing backed up in the first backup job and terminates at the controllerdata agent that executes on the second proxy; and wherein the secondproxy concurrently uses no more than the maximum limit of data streamsdetermined by the coordinator data agent for the second proxy based onthe operational properties of the second proxy. The above-recited methodwherein the coordinator data agent is configured for backing up, atleast in part, one or more virtual machines in the storage managementsystem.

The above-recited method wherein the controller data agent is configuredfor backing up, at least in part, one or more virtual machines in thestorage management system. The above-recited method wherein thecoordinator data agent and the controller data agent are virtual-serverdata agents, which are configured for backup of virtual machines in thestorage management system. The above-recited method wherein the firstset of virtual machines comprises a first subset of virtual machinesthat execute on a first host computing device, and a second subset ofvirtual machines that execute on a second host computing device. Theabove-recited method wherein the first proxy which hosts the coordinatordata agent executes on the same computing device as the first subset ofvirtual machines, such that the first computing device coincides withthe first host computing device. The above-recited method wherein thesecond host computing device which executes the second subset of virtualmachines is distinct from the second proxy which executes the controllerdata agent. The above-recited method may further comprise: designating,by the storage manager, a third data agent to act as a second controllerin the first backup job, wherein the third data agent executes on asecond virtual machine which is designated a third proxy, and whereinthe second virtual machine executes on a third computing device, whichis distinct from the first computing device that executes the firstvirtual machine; establishing inter-process communications between thecoordinator data agent and the second controller data agent; furthercollecting, by the coordinator data agent, information about operationalproperties of the third proxy; determining, by the coordinator dataagent, a respective maximum limit of data streams assignable to thethird proxy based on the operational properties of the third proxy;assigning, by the coordinator data agent, a first data stream to thethird proxy in the course of performing the first backup job, whereinthe first data stream originates at a first storage device comprisingvirtual-machine data being backed up in the first backup job andterminates at the second controller data agent that executes on thethird proxy; and wherein the second proxy concurrently uses, in thecourse of performing one or more backup jobs including the first backupjob, no more than the respective maximum limit of data streamsdetermined by the coordinator data agent for the third proxy based onthe operational properties of the third proxy.

The above-recited method may further comprise: collecting, by thecoordinator data agent, job-related information for executing the firstbackup job; and wherein the job-related information for executing thefirst backup job comprises one or more of: the identities of the firstset of virtual machines to be backed up, one or more operationalproperties of each virtual machine in the first set, information aboutone or more storage devices storing virtual-machine data to be backedup, and a maximum number of data streams allowed to be used concurrentlywhile performing the first backup job. The above-recited method whereinthe operational properties of each respective proxy for whichinformation is collected by the coordinator data agent comprise at leastone of: a processing capacity of the respective proxy, and an amount ofrandom-access memory of the respective proxy; and wherein the maximumlimit of data streams assignable to each respective proxy is based onthe at least one of: the processing capacity of the respective proxy,and the amount of random-access memory of the respective proxy. Theabove-recited method wherein the maximum limit of data streamsassignable to each respective proxy positively correlates to at leastone of: the processing capacity of the respective proxy, and the amountof random-access memory of the respective proxy. The above-recitedmethod may further comprise: establishing inter-process communicationsbetween the coordinator data agent and the controller data agent. Theabove-recited method wherein the job-related information for executingthe first backup job is collected by the coordinator data agent from astorage policy stored by the storage manager.

According to another illustrative embodiment of the present invention, acomputer-readable medium, excluding transitory propagating signals,storing instructions that, when executed by at least one computingdevice, may cause the computing device to perform a method for managingbackup operations in a storage management system, the method comprising:(I) collecting, by a designated coordinator for a first backup job in astorage management system, information about operational properties of afirst proxy and a second proxy, wherein the coordinator operates as thefirst proxy, wherein a designated controller operates as the secondproxy, and wherein the first backup job is associated with one or moresecondary copy operations for a first set of virtual machines; (II)determining, by the coordinator, a respective limit of data streams foreach of the first proxy and the second proxy, wherein the respectivelimit of data streams is based on the operational properties of eachrespective proxy; and (III) wherein each proxy is constrained by thelimit of data streams in the course of performing one or more backupjobs in the storage management system, including while performing thefirst backup job. The above-recited computer-readable medium wherein thecoordinator is a data agent that executes on a first computing devicehaving one or more processors and non-transitory computer-readablememory, and wherein the controller is a data agent that executes on afirst virtual machine, and wherein the first virtual machine executes ona second computing device having one or more processors andnon-transitory computer-readable memory. The above-recitedcomputer-readable medium wherein the limit of data streams for each ofthe first proxy and the second proxy is based on the at least one of:the processing capacity of the respective proxy, and the amount ofrandom-access memory of the respective proxy.

According to another example embodiment, a computer-implement method forgenerating an ordered priority list of a first set of virtual machinesto be backed up in a storage management system, the method to beexecuted by a computing device having one or more processors andnon-transitory computer-readable memory, the method may comprise: (I)associating each virtual machine in the first set of virtual machineswith one or more proxies from a set of candidate proxies in the storagemanagement system, wherein the associating includes determining which ofcandidate proxies are eligible to back up a respective virtual machine;(II) ordering the first set of virtual machines into a priority list inorder of increasing number of associated eligible proxies for therespective virtual machine; and (III) in the course of executing thefirst backup job, assigning to a first virtual machine in the first setbeing wherein the ordering into the priority list comprises breaking atie among a plurality of virtual machines in the first set by orderingthe virtual machines in the plurality in decreasing of the total amountof storage allocated to each respective virtual machine. Theabove-recited method wherein the ordering into the priority listcomprises breaking a tie among a plurality of virtual machines in thefirst set by ordering the virtual machines in the plurality indecreasing order of a storage-size metric associated with the respectivevirtual machine. The above-recited method wherein the storage-sizemetric for a given virtual machine is based on at least one of: a numberof storage units allocated to the given virtual machine, and arespective storage space for each of the number of storage units. Theabove-recited method wherein the storage-size metric for a given virtualmachine is based on a total amount of storage allocated to the givenvirtual machine, such that the breaking of the tie among the pluralityof virtual machines results in ordering the plurality of virtualmachines in decreasing order of the total amount of storage allocated toeach respective virtual machine. The above-recited method wherein eachvirtual machine in the ordered priority list is associated with at leastone eligible proxy. The above-recited method wherein a virtual machinein the ordered priority list is associated with a higher priority ifthat virtual machine is connected to a storage area network (SAN) or ifthat virtual machine has the largest amount of data to back up ascompared to other virtual machines in the first set of virtual machines.The above-recited method may further comprise: designating, by a storagemanager component of the storage management system, a first data agentto act as coordinator of the first backup job, wherein the first backupjob is configured to perform secondary copy operations for the first setof virtual machines in the storage management system, and wherein thecoordinator data agent executes on a first computing device having oneor more processors and non-transitory computer-readable memory which isdesignated a first proxy; designating, by the storage manager, a seconddata agent to act as controller in the first backup job, wherein thecontroller data agent executes on a second computing device having oneor more processors and non-transitory computer-readable memory which isdesignated a second proxy; and wherein any given eligible proxy executesa data agent that is suitable for backing up data associated with theone or more virtual machines that the respective proxy is eligible toback up.

According to yet another illustrative embodiment, a computer-readablemedium, excluding transitory propagating signals, storing instructionsthat, when executed by at least one computing device, each computingdevice having one or more processors and non-transitorycomputer-readable memory, may cause the computing device to perform amethod for generating an ordered priority list of a first set of virtualmachines to be backed up in a storage management system, the methodcomprising: (I) associating each virtual machine in the first set ofvirtual machines with one or more proxies from a set of candidateproxies in the storage management system, wherein the associatingincludes determining which of candidate proxies are eligible to back upa respective virtual machine; (II) ordering the first set of virtualmachines into a priority list in order of increasing number ofassociated eligible proxies for the respective virtual machine; and(III) in the course of executing the first backup job, assigning to afirst virtual machine in the first set being backed up, a first eligibleproxy based on the ordered priority list. The above-recitedcomputer-readable medium wherein the ordering into the priority listcomprises breaking a tie among a plurality of virtual machines in thefirst set by ordering the virtual machines in the plurality indecreasing of the total amount of storage allocated to each respectivevirtual machine. The above-recited computer-readable medium wherein eachvirtual machine in the ordered priority list is associated with at leastone eligible proxy. The above-recited computer-readable medium wherein avirtual machine in the ordered priority list is associated with a higherpriority if that virtual machine is connected to a storage area network(SAN) or if that virtual machine has the largest amount of data to backup as compared to other virtual machines in the first set of virtualmachines. The above-recited computer-readable medium wherein the methodfurther comprises: designating, by a storage manager component of thestorage management system, a first data agent to act as coordinator ofthe first backup job, wherein the first backup job is configured toperform secondary copy operations for the first set of virtual machinesin the storage management system, and wherein the coordinator data agentexecutes on a first computing device having one or more processors andnon-transitory computer-readable memory which is designated a firstproxy; designating, by the storage manager, a second data agent to actas controller in the first backup job, wherein the controller data agentexecutes on a second computing device having one or more processors andnon-transitory computer-readable memory which is designated a secondproxy; and wherein any given eligible proxy executes a data agent thatis suitable for backing up data associated with the one or more virtualmachines that the respective proxy is eligible to back up.

According to another example embodiment of the present invention, acomputer-readable medium, excluding transitory propagating signals,storing instructions that, when executed by at least one computingdevice having one or more processors and non-transitorycomputer-readable memory, cause the computing device to perform a methodcomprising: (I) identifying one or more proxies in a storage managementsystem that are eligible to back up a given virtual machine in a firstset of virtual machines in the storage management system, wherein anyone proxy among the one or more proxies represents one of: (a) a firstvirtual machine that executes on a first computing device, wherein thefirst virtual machine executes a data agent for virtual-machine backup,and (b) a second computing device that executes a data agent forvirtual-machine backup; (II) wherein the identifying comprises: (i)determining (A) a set of candidate proxies that are candidates to backup the given virtual machine, and (B) a mode of access available to eachrespective candidate proxy for accessing the given virtual machine'sdata as a source for backup, wherein the mode of access has a predefinedtier of preference; (ii) classifying each candidate proxy in the set ofcandidate proxies based on the predefined tier of preference for therespective candidate proxy's mode of access to the given virtualmachine's data as the source for backup; and (iii) defining one or morecandidate proxies that are classified as having the highest-tier ofpreference as being eligible to back up the given virtual machine.

According to another embodiment, a computer-readable medium, excludingtransitory propagating signals, storing instructions that, when executedby at least one computing device having one or more processors andnon-transitory computer-readable memory, may cause the computing deviceto perform a method comprising: (I) identifying a plurality of proxiesfor collectively backing up the set of virtual machines in a storagemanagement system, wherein any one proxy among the plurality of proxiesrepresents one of: (a) a first virtual machine that executes on a firstcomputing device, wherein the first virtual machine executes a firstvirtual-server data agent for virtual-machine backup, and (b) a secondcomputing device that executes the first virtual-server data agent forvirtual-machine backup; (II) identifying a first proxy among theplurality of proxies, wherein the first proxy is available for backupusing a first data stream which terminates at the first proxy; (III)identifying a second virtual machine on a priority list that identifiesa set of virtual machines awaiting backup, wherein the priority listorders the set of virtual machines in increasing order of the number ofproxies that are eligible to back up each respective virtual machine;and (IV) if the first proxy is eligible to back up the second virtualmachine and a score of the second virtual machine's data store is undera predefined threshold, causing a backup process for the second virtualmachine to be launched at the first proxy, wherein the first proxy backsup, at least in part, the second virtual machine using the first datastream, and wherein the first data stream originates at a first storagedevice comprising the second virtual machine's data store. Theabove-recited computer-readable medium wherein the set of virtualmachines awaiting backup is associated with a backup job in the storagemanagement system.

According to yet one more embodiment of the present invention, acomputer-implemented method for identifying a next available proxy forvirtual-machine backup based on stream utilization at the proxy, themethod to be executed by one or more computing devices having one ormore respective processors and respective computer-readable memory, themethod comprising: (I) defining, by a coordinator data agent thatoperates as a component of the storage management system, a set ofcandidate proxies for a virtual-machine backup job in the storagemanagement system, wherein any one proxy in the set of candidate proxiesrepresents one of: (a) a first virtual machine that executes on a firstcomputing device having one or more processors and non-transitorycomputer-readable memory, wherein the first virtual machine executes afirst virtual-server data agent for virtual-machine backup, and (b) asecond computing device having one or more processors and non-transitorycomputer-readable memory, wherein the second computing device executesthe first virtual-server data agent; (II) evaluating, by the coordinatordata agent, the set of candidate proxies, wherein the evaluating for agiven candidate proxy in the set of candidate proxies comprises:determining a maximum limit of data streams assignable to the givencandidate proxy, based on operational properties of the given candidateproxy, identifying a number of data streams that are currently active atthe given candidate proxy, including any data streams in thevirtual-machine backup job and any data streams for other jobs in thestorage management system, computing a data stream utilization score forthe given candidate proxy, based on a ratio of (i) the number of datastreams currently active at the given candidate proxy to (ii) themaximum limit of data streams assignable to the given candidate proxy,wherein any data stream considered in the evaluating operationterminates at the given candidate proxy; and (III) after evaluating theset of candidate proxies, assigning a new data stream, by thecoordinator data agent, to a first proxy in the set of candidate proxiesthat has the lowest data stream utilization score among the set ofcandidate proxies.

The above-recited method wherein, in the course of performing operationsfor one or more backup jobs in the storage management system includingfor the virtual-machine backup job, the first proxy may concurrently useno more than the respective maximum limit of data streams assignable tothe first proxy. The above-recited method wherein the operationalproperties of the first proxy comprise at least one of: a processingcapacity of the first proxy, and an amount of random-access memory ofthe first proxy; and wherein the maximum limit of data streamsassignable to the first proxy is based on the at least one of: theprocessing capacity of the first proxy, and the amount of random-accessmemory of the first proxy. The above-recited method wherein the maximumlimit of data streams assignable to the first proxy positivelycorrelates to at least one of: the processing capacity of the firstproxy, and the amount of random-access memory of the first proxy. Theabove-recited method may further comprise: identifying, by thecoordinator data agent, a second virtual machine on a priority list thatidentifies a set of virtual machines awaiting backup in thevirtual-machine backup job; and causing, by the coordinator data agent,a backup process for the second virtual machine to be launched at thefirst proxy using the new data stream.

In other embodiments, a system or systems may operate according to oneor more of the methods and/or according to the computer-readable mediarecited in the preceding paragraphs. In yet other embodiments, a methodor methods may operate according to one or more of the systems and/oraccording to the computer-readable media recited in the precedingparagraphs. In yet more embodiments, a computer-readable medium ormedia, excluding transitory propagating signals, may cause one or morecomputing devices having one or more processors and non-transitorycomputer-readable memory to operate according to one or more of thesystems and/or methods recited in the preceding paragraphs.

According to another embodiment, a computer-implemented method mayperform as generally shown and described herein and equivalents thereof.Likewise, a system as generally shown and described herein andequivalents thereof. Likewise, a tangible non-transitorycomputer-readable medium storing instructions, which when executed by atleast one computing device, cause the computing device to perform amethod as generally shown and described herein and equivalents thereof.

Terminology

Conditional language, such as, among others, “can,” “could,” “might,” or“may,” unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or steps. Thus, such conditional language is notgenerally intended to imply that features, elements and/or steps are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or without userinput or prompting, whether these features, elements and/or steps areincluded or are to be performed in any particular embodiment.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” As used herein, the terms “connected,”“coupled,” or any variant thereof means any connection or coupling,either direct or indirect, between two or more elements; the coupling orconnection between the elements can be physical, logical, or acombination thereof. Additionally, the words “herein,” “above,” “below,”and words of similar import, when used in this application, refer tothis application as a whole and not to any particular portions of thisapplication. Where the context permits, words in the above DetailedDescription using the singular or plural number may also include theplural or singular number respectively. The word “or” in reference to alist of two or more items, covers all of the following interpretationsof the word: any one of the items in the list, all of the items in thelist, and any combination of the items in the list. Likewise the term“and/or” in reference to a list of two or more items, covers all of thefollowing interpretations of the word: any one of the items in the list,all of the items in the list, and any combination of the items in thelist.

Depending on the embodiment, certain operations, acts, events, orfunctions of any of the algorithms described herein can be performed ina different sequence, can be added, merged, or left out altogether(e.g., not all are necessary for the practice of the algorithms).Moreover, in certain embodiments, operations, acts, functions, or eventscan be performed concurrently, e.g., through multi-threaded processing,interrupt processing, or multiple processors or processor cores or onother parallel architectures, rather than sequentially.

Systems and modules described herein may comprise software, firmware,hardware, or any combination(s) of software, firmware, or hardwaresuitable for the purposes described herein. Software and other modulesmay reside and execute on servers, workstations, personal computers,computerized tablets, PDAs, and other computing devices suitable for thepurposes described herein. Software and other modules may be accessiblevia local memory, via a network, via a browser, or via other meanssuitable for the purposes described herein. Data structures describedherein may comprise computer files, variables, programming arrays,programming structures, or any electronic information storage schemes ormethods, or any combinations thereof, suitable for the purposesdescribed herein. User interface elements described herein may compriseelements from graphical user interfaces, interactive voice response,command line interfaces, and other suitable interfaces.

Further, the processing of the various components of the illustratedsystems can be distributed across multiple machines, networks, and othercomputing resources. In addition, two or more components of a system canbe combined into fewer components. Various components of the illustratedsystems can be implemented in one or more virtual machines, rather thanin dedicated computer hardware systems and/or computing devices.Likewise, the data repositories shown can represent physical and/orlogical data storage, including, for example, storage area networks orother distributed storage systems. Moreover, in some embodiments theconnections between the components shown represent possible paths ofdata flow, rather than actual connections between hardware. While someexamples of possible connections are shown, any of the subset of thecomponents shown can communicate with any other subset of components invarious implementations.

Embodiments are also described above with reference to flow chartillustrations and/or block diagrams of methods, apparatus (systems) andcomputer program products. Each block of the flow chart illustrationsand/or block diagrams, and combinations of blocks in the flow chartillustrations and/or block diagrams, may be implemented by computerprogram instructions. Such instructions may be provided to a processorof a general purpose computer, special purpose computer,specially-equipped computer (e.g., comprising a high-performancedatabase server, a graphics subsystem, etc.) or other programmable dataprocessing apparatus to produce a machine, such that the instructions,which execute via the processor(s) of the computer or other programmabledata processing apparatus, create means for implementing the actsspecified in the flow chart and/or block diagram block or blocks.

These computer program instructions may also be stored in anon-transitory computer-readable memory that can direct a computer orother programmable data processing apparatus to operate in a particularmanner, such that the instructions stored in the computer-readablememory produce an article of manufacture including instruction meanswhich implement the acts specified in the flow chart and/or blockdiagram block or blocks. The computer program instructions may also beloaded onto a computing device or other programmable data processingapparatus to cause a series of operations to be performed on thecomputing device or other programmable apparatus to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide steps for implementingthe acts specified in the flow chart and/or block diagram block orblocks.

Any patents and applications and other references noted above, includingany that may be listed in accompanying filing papers, are incorporatedherein by reference. Aspects of the invention can be modified, ifnecessary, to employ the systems, functions, and concepts of the variousreferences described above to provide yet further implementations of theinvention.

These and other changes can be made to the invention in light of theabove Detailed Description. While the above description describescertain examples of the invention, and describes the best modecontemplated, no matter how detailed the above appears in text, theinvention can be practiced in many ways. Details of the system may varyconsiderably in its specific implementation, while still beingencompassed by the invention disclosed herein. As noted above,particular terminology used when describing certain features or aspectsof the invention should not be taken to imply that the terminology isbeing redefined herein to be restricted to any specific characteristics,features, or aspects of the invention with which that terminology isassociated. In general, the terms used in the following claims shouldnot be construed to limit the invention to the specific examplesdisclosed in the specification, unless the above Detailed Descriptionsection explicitly defines such terms. Accordingly, the actual scope ofthe invention encompasses not only the disclosed examples, but also allequivalent ways of practicing or implementing the invention under theclaims.

To reduce the number of claims, certain aspects of the invention arepresented below in certain claim forms, but the applicant contemplatesthe various aspects of the invention in any number of claim forms. Forexample, while only one aspect of the invention is recited as ameans-plus-function claim under 35 U.S.C sec. 112(f) (AIA), otheraspects may likewise be embodied as a means-plus-function claim, or inother forms, such as being embodied in a computer-readable medium. Anyclaims intended to be treated under 35 U.S.C. § 112(f) will begin withthe words “means for”, but use of the term “for” in any other context isnot intended to invoke treatment under 35 U.S.C. § 112(f). Accordingly,the applicant reserves the right to pursue additional claims afterfiling this application, in either this application or in a continuingapplication.

What is claimed is:
 1. A computer-readable medium, excluding transitorypropagating signals, storing instructions that, when executed by acomputing device having one or more processors and non-transitorycomputer-readable memory, cause the computing device to perform a methodcomprising: identifying, by a first data agent executing on thecomputing device, one or more proxies in a storage management systemthat are eligible to back up a given virtual machine in a first set ofvirtual machines in the storage management system, wherein any one proxyamong the one or more proxies is one of: (a) a first virtual machinethat executes on a first computing device, wherein the first virtualmachine executes a second data agent for virtual-machine backup, and (b)a second computing device that executes a second data agent forvirtual-machine backup; wherein the identifying comprises: (i)determining (A) a set of candidate proxies for backing up the givenvirtual machine, and (B) a mode of access available to each respectivecandidate proxy for accessing the given virtual machine's data as asource for backup, wherein the mode of access has a predefined tier ofpreference, wherein the determining is based on analyzing, by the firstdata agent, data from a database that is associated with a storagemanager component that manages the storage management system, andwherein the storage manager component designates the first data agent asa coordinator data agent for a first backup job for the first set ofvirtual machines, (ii) classifying each candidate proxy in the set ofcandidate proxies based on the predefined tier of preference for therespective candidate proxy's mode of access to the given virtualmachine's data as the source for backup, and (iii) defining one or morecandidate proxies that are classified in a highest tier of preference asbeing eligible to back up the given virtual machine; and wherein if thedefining results in the given virtual machine being stranded without aneligible proxy, subsequently defining one or more candidate proxies,which are classified in a next highest tier of preference that is lessthan the highest tier of preference, as being eligible to back up thegiven virtual machine.
 2. The computer-readable medium of claim 1,wherein a first mode of access wherein a candidate proxy has directaccess to the given virtual machine's data via a storage area networkhas a higher tier of preference than a second mode of access wherein thecandidate proxy is a virtual machine that executes on the same computingdevice as the given virtual machine to be backed up and has local accessto the given virtual machine's data from the same computing device. 3.The computer-readable medium of claim 2, wherein the second mode ofaccess has a higher tier of preference than a third mode of accesswherein the candidate proxy is a virtual machine that executes on adifferent computing device from the given virtual machine to be backedup and has networked access to the given virtual machine's data.
 4. Thecomputer-readable medium of claim 2, wherein the second mode of accesshas a higher tier of preference than a fourth mode of access wherein thecandidate proxy has networked access to the given virtual machine's dataas a network block device.
 5. A method for generating a priority list ofa first set of virtual machines to be backed up in a storage managementsystem, the method comprising: associating each virtual machine in thefirst set of virtual machines with one or more proxies from a set ofcandidate proxies in the storage management system, wherein theassociating includes determining which of the set of candidate proxiesare eligible to back up a respective virtual machine, and wherein anyone candidate proxy among the set of candidate proxies is one of: (a) afirst virtual machine that executes on a first computing device, whereinthe first virtual machine executes a second data agent forvirtual-machine backup, and (b) a second computing device that executesa second data agent for virtual-machine backup, and wherein if a givenvirtual machine in the first set is not associated with at least oneeligible proxy having a highest tier of preference for a transport modebetween the at least one eligible proxy and the given virtual machine'sdata, associating the given virtual machine with one or more candidateproxies having a next highest tier of preference that is less than thehighest tier of preference; ordering the first set of virtual machinesinto a priority list in order of increasing number of associatedeligible proxies for each respective virtual machine; while executing afirst backup job, assigning to a first virtual machine in the first set,a first eligible proxy based on the priority list, wherein the seconddata agent executing on the assigned first eligible proxy participatesin a backup of the first virtual machine during the first backup job;and wherein the associating, the ordering, and the assigning areperformed by a first data agent designated a coordinator data agent forthe first backup job, and wherein a storage manager that manages thestorage management system designates the first data agent to be thecoordinator data agent.
 6. The method of claim 5 wherein the orderinginto the priority list comprises breaking a tie among a plurality ofvirtual machines in the first set by ordering the virtual machines inthe plurality in decreasing order of a total amount of storage allocatedto each respective virtual machine.
 7. The method of claim 5 wherein agiven virtual machine has a higher priority in the priority list whenone of:the given virtual machine is connected to a storage area networkand when the given virtual machine has more data to back up than othervirtual machines in the first set of virtual machines.
 8. The method ofclaim 5 wherein the first backup job is configured to perform secondarycopy operations for the first set of virtual machines in the storagemanagement system, and wherein the coordinator data agent executes on afirst computing device having one or more processors and non-transitorycomputer-readable memory which is designated a first proxy.
 9. Themethod of claim 8 wherein any given eligible proxy executes a data agentthat is suitable for backing up data associated with one or more virtualmachines that the given proxy is eligible to back up.
 10. A method forgenerating a priority list of a first set of virtual machines to bebacked up in a storage management system, the method comprising:designating, by a storage manager that manages a data storage managementsystem, a first virtual-server data agent as a coordinator data agentfor a first backup job of the first set of virtual machines;associating, by the coordinator data agent, each virtual machine in thefirst set of virtual machines with one or more proxies from a set ofcandidate proxies in the storage management system, wherein theassociating includes determining which of the set of candidate proxiesare eligible to back up a respective virtual machine, and wherein theassociating results in each virtual machine in the first set beingassociated with at least one eligible proxy, and wherein if a givenvirtual machine in the first set is not associated with at least oneeligible proxy having a highest tier of preference for a transport modebetween the at least one eligible proxy and the given virtual machine'sdata, associating the given virtual machine with one or more candidateproxies having a next highest tier of preference that is less than thehighest tier of preference; ordering, by the coordinator data agent, thefirst set of virtual machines into a priority list in order ofincreasing number of associated eligible proxies for each respectivevirtual machine; and assigning, by the coordinator data agent, based onthe priority list, a first eligible proxy to a first virtual machine inthe first set of virtual machines, wherein the assigned first eligibleproxy is to perform one or more storage operations for the first virtualmachine during the first backup job.
 11. The method of claim 10 whereinthe ordering into the priority list comprises breaking a tie among aplurality of virtual machines in the first set by ordering the virtualmachines in the plurality in decreasing order of a total amount ofstorage allocated to each respective virtual machine.
 12. The method ofclaim 10 wherein a given virtual machine has a higher priority in thepriority list when the given virtual machine is one of: (a) connected toa storage area network (SAN), and (b) has more data to back up thanother virtual machines in the first set of virtual machines.
 13. Themethod of claim 10 wherein the coordinator data agent executes on afirst computing device having one or more processors and non-transitorycomputer-readable memory which is designated a first proxy.
 14. Themethod of claim 10 wherein the coordinator data agent executes on avirtual machine hosted by a first computing device having one or moreprocessors and non-transitory computer-readable memory which isdesignated a first proxy.
 15. The method of claim 10 wherein any giveneligible proxy executes a data agent that is suitable for backing updata associated with one or more virtual machines that the given proxyis eligible to back up.